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date: 27 January 2022

The Implications of Informal Settlement Upgrading Programs for Access to Water, Sanitation, and Public Healthfree

The Implications of Informal Settlement Upgrading Programs for Access to Water, Sanitation, and Public Healthfree

  • David SatterthwaiteDavid SatterthwaiteInternational Institute for Environment and Development
  •  and Alice SverdlikAlice SverdlikInternational Institute for Environment and Development


Most cities in low- and middle-income countries have substantial proportions of their population living in informal settlements—sometimes up to 60% or more. These also house much of the city’s low-income workforce; many informal settlements also concentrate informal economic activities. These settlements usually lack good provision for water, sanitation, and other essential services.

The conventional government responses were to bulldoze them or ignore them. But from the 1960s, another approach became common—upgrading settlements to provide missing infrastructure (e.g., water pipes, sewers, drains). In the last 20 years, community-driven upgrading has become increasingly common. Upgrading initiatives are very diverse. At their best, they produce high-quality and healthy living conditions and services that would be expected to greatly reduce illness, injury or disablement, and premature death. But at their worst, upgrading schemes provide a limited range of improvements do nothing to reduce the inhabitants’ exclusion from public services.

There is surprisingly little research on upgrading’s impact on health. One reason is the very large number of health determinants at play. Another is the lack of data on informal settlement populations.

Much of the innovation in upgrading is in partnerships between local governments and organizations formed by informal settlement residents, including slum/shack dweller federations that are active in over 30 nations.

Community-driven processes can deal with issues that are more difficult for professionals to resolve—including mapping and enumerations. Meanwhile, local government can provide the connections to all-weather roads, water mains, sewers, and storm drains into which communities can connect.


  • Environmental Health
  • Public Health Policy and Governance


Upgrading programs should transform health in informal settlements, given their strong potential to support the environmental, social, and political determinants of health. Although the scale and scope of upgrading initiatives vary widely, they often enhance the living conditions of marginalized neighborhoods and can also form the basis of inclusive partnerships with government agencies and officials. So there is a great interest in the extent to which these initiatives can improve provision for water and sanitation and contribute in other ways to public health (Corburn & Sverdlik, 2017; Henson et al., 2020). But it is challenging to collect relevant data in such settlements and even more so to separate out the health impacts of improving water and sanitation from the many other factors that influence residents’ health.

New approaches to health data collection have been generated directly by informal settlement residents and their community organizations (Chitekwe-Biti et al., 2012; Livengood & Kunte, 2012; Satterthwaite et al., 2019). These have shown great potential to support and inform more effective upgrading programs and their water and sanitation components; there are also strong possibilities to strengthen relations with local government via grassroots data collection (Patel et al., 2012). Even local governments with very limited funds can do much to support community-driven upgrading.

This article explores the range of upgrading initiatives, how they vary in the scale and scope of what was done, and who drove and/or supported such interventions. What issues does this analysis bring to the fore? It indicates the widespread acceptance by (many municipal) governments of informal settlement upgrading programs. This includes local governments’ preparedness to improve water and sanitation—a different approach from conventional housing developments and from policies that bulldozed informal settlements or ignored them (especially if they were not visible and/or not on valuable land). But many national and city governments have not significantly changed their approach. In other instances, a government department responsible for infrastructure can bulldoze informal settlements while its own housing department is still supporting upgrading. The local political barriers to upgrading need more attention in future research. Key lessons for research and practice are discussed in order to help fulfill the potential of upgrading for its inhabitants’ health, well-being, and inclusion.

This article drew on many sources, including three papers that review health issues in a range of slum or informal settlement upgrading initiatives. Two are systematic reviews: Henson et al. (2020) and Turley et al. (2013). The third, Corburn and Sverdlik (2016), reviews how health issues are addressed in the documentation on 18 urban slum-upgrading projects or programs.

This article also draws on two papers in The Lancet developed by a group of researchers working on “slums” and health, and assembled by Richard Lilford (Lilford et al., 2016; see also Ezeh et al., 2017). The article also makes use of reviews of the literature on risks and vulnerabilities to climate change for urban areas (Revi et al., 2014) and for informal settlements (Satterthwaite et al., 2020), as well as on recently published case studies of upgrading schemes that include some consideration of health or determinants of health. The authors also draw on their past reviews of relevant literature—for instance, Corburn and Sverdlik (2016) and Sverdlik (2011)—and their fieldwork in informal settlements, working on health issues over the last 3 decades (see, e.g., Hardoy et al., 1990).

Background: “Upgrading” and Its Potential Benefits

Informal settlement upgrading programs, at their best, produce high-quality and healthy living conditions and services, and secure tenure that would be expected to greatly reduce illness, injury or disablement, and premature death. They can provide all inhabitants with good-quality water piped to their homes, private toilets and bathrooms, and connection to sewers or other high-quality sanitation solutions while also promoting links to the formal city, as in many Latin American upgrading programs (Rojas, 2010; Sette Whitaker Ferreira et al., 2020). They also bring other benefits—for many including registered addresses that usually serve as the means to access government schools and healthcare and the possibilities to get insurance for homes and possessions (Farvacque-Vitkovic et al., 2005). They may be needed to get on the voter registry. There are health benefits for the neighborhood too, from enhanced solid waste collection, to storm and surface water drains, to public lighting (Corburn & Sverdlik, 2017; Ezeh et al., 2017; Lilford et al., 2016). Upgrading rental housing can also benefit tenants, but it is more difficult to ensure this (particularly because of the likelihood of rising rents).

Upgrading done well can contribute much to reducing health risks and impacts from climate change in informal settlements (Collado & Wang, 2020; Revi et al., 2014). The Intergovernmental Panel on Climate Change’s (IPCC) Fifth Assessment highlights the importance of informal settlement upgrading for reducing the impacts of extreme weather in high-risk areas (Revi et al., 2014) and the particular importance of providing “risk-reducing” infrastructure: piped water that is safe, sufficient, and affordable; good-quality sanitation and electricity; all-weather access roads; storm and surface drainage; street lighting; and risk-reducing services (including hospitals and healthcare, emergency services, road traffic management, and the rule of law) (Revi et al., 2014). Indeed, the list of the IPCC’s risk-reducing infrastructure and services is almost identical to that for comprehensive upgrading (see “Diverse Forms of Upgrading”). Informal settlement upgrading, if done well, can also be seen as a major contribution to household and community adaptation to the health impacts of climate change (Satterthwaite et al., 2020).

Some of the services provided by upgrading have obvious relevance to addressing Covid‑19, although this often has more to do with what grassroots organizations in informal settlements are doing (e.g., mutual support and outreach by community health workers).

One of the difficulties facing any review of upgrading informal settlements and health is what to include in the term upgrading. There are so many influential physical, social, environmental, and political determinants of health. Does upgrading need to include physical improvements, or can it only include services—for instance, improving provision for public transport or policing? Should an initiative to pave access roads be considered upgrading? Should measures that just improve water or sanitation be included as upgrading? Then, when assessing health benefits that can come from upgrading, should consideration be given to changes in incomes, given their influence on health?

Should the provision of public toilets and washing facilities be counted as upgrading, especially where these are often poorly maintained and managed? In some contexts, where these are redesigned, built, and managed by community organizations, public toilets can bring many health benefits (Burra et al., 2003).

There are case studies of “upgrading” that are actually eviction, pushing residents out of their homes and settlements and then rebuilding, but with residents receiving no support or any compensation for alternative accommodation while the houses are being built, or any compensation. They may not be able to access “upgraded” dwellings (Patel, 2013). In “Informal Settlements,” the discussion turns to key trends in informal settlements and seeks to define these areas more carefully, while noting the significant shortfalls in reliable data on informal settlements.

Informal Settlements

In 2020, the world’s urban population reached 4.4 billion; 3.4 billion of this in urban centers in what the UN has termed “less developed regions” (UN Department of Economic and Social Affairs, 2018). Over the next 3 decades, UN projections suggest a growth in the urban population in “less developed regions” of over 2 billion residents; most of this growth will be in Asia and Africa. So, another 2 billion urban dwellers will require housing, infrastructure and services, alongside support to adapt to climate change. And as highlighted by the COVID-19 pandemic, global and local public health capacities will need to be bolstered, including to serve residents of informal settlements (Corburn et al., 2020).

Because so many informal settlements go unrecorded, there are no accurate statistics on their population; the United Nations’ estimates suggest that around a billion urban dwellers live in informal settlements (often in poor-quality, overcrowded houses or shacks).1 Case studies in many cities show that they typically have 30%–60% of their populations living in informal settlements (Satterthwaite et al., 2020). But the lack of data on informal settlements globally makes it impossible to estimate their share in housing population and how this is changing. The UNICEF/WHO Joint Monitoring Programme (JMP) that is responsible for gathering and publishing global and national statistics for water, sanitation, and hygiene (WASH) currently produces no statistics for individual cities; thus it cannot have WASH statistics for informal settlements (see WHO & UNICEF, n.d., for JMP data). Most national governments do not produce these WASH figures, even though their censuses include or should include data on all households; there is no marker to allow census data on informal settlements to be separated from other households (Lilford et al., 2016).

The assumption that informal settlement populations are growing is challenged by data on housing in Latin America, and perhaps there are other nations where this is also so. Certainly, at city level in Latin America, there are many cities where the proportion of the population in informal settlements has fallen and the percent with good-quality WASH has increased (Rojas, 2018).

Informal settlements are not the same as “slums,” although a considerable portion of the population living in informal settlements could be classified as living in slums. Definitions of informal settlements are based on contraventions of specific laws, rules, and regulations. The definition used by the OECD is “areas where groups of housing units have been constructed on land that the occupants have no legal claim to or occupy illegally” or “unplanned settlements and areas where housing is not in compliance with current planning and building regulations (unauthorized housing)” (OECD, 2001). Meanwhile, definitions of slums are usually based on measures of housing quality, the adequacy of service provision, and residential density (United Nations Human Settlements Programme Staff and United Nations Human Settlements Programme, 2003). So, slums and informal settlements are not synonymous (although they are often treated as such). Most informal settlements fit within “slum” definitions, but they also include settlements that have developed conventional housing and provision of basic services.

This article focuses on upgrading initiatives that include physical improvements, with a particular interest in water and sanitation and with consideration given to the relationships and changes in the relationships between informal settlement dwellers and their governments.

Housing and Health in Informal Settlements

There is a growing interest in informal settlements and health, but this was also the case in the late 1980s, and subsequently there was lost momentum. Although the literature on health issues in informal settlements is sparse, the large health burdens faced by those living in informal settlements has been recognized for many decades (see, e.g., Hardoy et al., 1990; WHO, 1991, 1992a, 1992b; World Commission on Environment and Development, 1987). There are also other housing forms that are not informal, but have high health risks—for instance, overcrowded poor-quality tenements that are often termed “slums” or become slums (Huchzermeyer, 2011). Recently, there has been renewed interest in health issues in informal settlements and responses to them (see African Population and Health Research Center [APHRC], 2014; Ezeh et al., 2017; Lilford et al., 2016; Sverdlik, 2011).

Health risks in informal settlements include not only infectious and parasitic diseases and chemical pollutants in the home, workplace, neighborhood, and city, but also physical hazards such as house structures poorly insulated against extreme temperatures and located on sites with high risks from landslides or flooding (Haines et al., 2013; Hardoy et al., 2001).

People who live in informal settlements often face not only many health risks but also multiple disadvantages that impact health, including low and unstable incomes, insecurity of tenure (especially tenants), and absence of rights and state entitlements (Ezeh et al., 2017; Mitlin & Satterthwaite, 2013). Many upgrading programs have narrowly focused on physical hazards and infrastructure; they generally lack the resources and capacities to address social inequality or very low incomes. One response to an upgraded informal settlement in Guatemala City was that this simply put a roof over their poverty because it did not address their very inadequate incomes (Díaz et al., 2001). This helps explain how other pressing issues beyond physical improvements were introduced into upgrading, such as enhanced policing and violence prevention (Matzopoulos et al., 2020; Roy et al., 2004).

There is a much larger body of literature on the very poor housing and living conditions in such settlements that has little information on health outcomes but does include details of many influential social, economic, political, environmental, or physical determinants of health. For instance, there is a large literature on the inadequacies in provision for water, sanitation, and hygiene and how many informal settlements are on sites at high risk of floods or landslides (Douglas et al., 2008; Williams et al., 2019). This often emphasizes the importance of addressing these and other health risks in what came to be termed “upgrading.”

One important change in how health and health interventions are seen comes from a recognition that the health of all individuals and households is impacted by a great range of factors. Hence the interest in what came to be called the “social determinants of health” (Friel et al., 2011), which also came to include economic, political, social, and environmental determinants. These made evident the large range of such determinants that influence health outcomes—from global and national influences to municipal or local contexts, to living and working conditions and access to services, to community organizations and health-seeking behaviors (see Figure 1).

Figure 1. The many economic, social, political and environmental determinants of health in urban areas.

Source: Mitlin and Satterthwaite (2013). An early version of this figure was presented and discussed in Cairncross et al. (1990). It has been improved and added to since then (see, e.g., Kjellstrom & Mercado, 2008; Vlahov et al., 2011).

Turley et al. (2013) presented another determinant of the health framework, focusing on slum upgrading, which also noted the range and diversity of determinants that influence health outcomes. The authors noted how these are too broad to be assessed in a single systematic review. Their analysis “focused on upgrading interventions involving physical environment and infrastructure improvements, with or without the integration of wider slum upgrading approaches (for example, policy, legal, financial, community action, social or service interventions)” (p. 10).

Water and Sanitation in Informal Settlements

There is a broad spectrum of deficiencies in the scale and range of water and sanitation provision in informal settlements. For instance, in Bangalore, “slums” include consolidated informal settlements, classified as slums, with conventional formal provision for water and sanitation; they also include temporary camps such as tent settlements that have no formal WASH (Krishna et al., 2014). Figure 2 shows the spectrum of provision for water and sanitation and their implications for health.

Figure 2. The spectrum of provision for water and sanitation and their implications for health.

A recent World Resources Institute (WRI) study on water supply and sanitation in urban areas (Mitlin et al., 2019) chose 15 cities on which to focus, five each in Latin America, Asia, and Africa. In each city, local researchers produced a report with an assessment of water and sanitation provision in one centrally located informal settlement. Of course, the selected informal settlement was not necessarily representative of the city’s other informal settlements.

For water, the study found that four of the informal settlements had 98%–100% of households with piped water to their home—and all were in the Latin American cities. Among all 15 settlements, a total of five had less than a quarter of their population with water piped to premises (two of these were in Africa, three in Asia).

The percentage of households with a private sanitation facility was 100% in four settlements, including those in Caracas, Cochabamba, Karachi, and São Paulo. It was 99% in Santiago de Cali, 97% in Rio de Janeiro, and 93% in Colombo. Meanwhile, the percentage with shared sanitation was highest in informal settlements in Nairobi (85%) and Lagos (65%). The percentage of households without access to private facilities was 55% in Mumbai and 10%–15% in informal settlements in Mzuzu (Malawi) and Lagos, respectively.

Sanitation service provision in the 15 informal settlements differs considerably based on a variety of factors, including when the neighborhood was established, the availability and ownership of the land, residential density, location of the settlement, the extent to which standards and regulations are enforced, and collective practices.

Perhaps surprisingly, there were informal settlements in which 99%–100% of households are connected to sewers in Bengaluru, Caracas, Cochabamba, and Santiago de Cali. In contrast, the informal settlements with no access to sewers were found in most other cities, including all the sub-Saharan African cities. Instead, most sanitation provision in these areas came from private septic tanks or pit latrines.

Seeing this variation raises some issues. Sewers are generally considered to be too expensive for low- and middle-income nations, yet in some cities (mostly in Latin America) these have been extended to nearly all informal settlement residents.

Many case studies show the deficient provision for water and sanitation, such as in the Alkodhar settlement. Located on the outskirts of Mogadishu, it was formed in 2012 and has 307 households—including many internally displaced persons who came during the 2011–2020 drought and, more recently, those who were evicted from more central city locations (Bonnet et al., 2020). For water, there are communal water taps built by NGOs, but not enough, so the residents have to access water from expensive mobile vendors. Some entrepreneurial businesses have dug wells from which they pipe water to the settlements at a cost. Sanitation is a challenge. The settlement has seven free-to-use latrines for 307 households, and queues are long, especially in the morning. Many residents have no choice but to use the bush, and at night this is a security risk for women and girls. Women prefer to live in the center of the settlement, where they feel better protected, especially at night. It is also closer to the latrines and water taps. At night, a number of male IDP (internally displaced person) volunteers patrol the settlement to keep out potential criminals.

There are important gender dimensions to inadequate WASH in informal settlements: Women and girls are often especially burdened by water collection (such as enduring lengthy queues at public taps and the physical effort needed to take the water home) and by inadequate sanitation. Women are more likely to shoulder childcare burdens linked to inadequate WASH (e.g., tending to children ill with diarrhea); there are often gender-inequitable time burdens of collecting water, as well as women’s greater need for privacy in sanitation (particularly during menstruation).2 Thus, the lack of adequate WASH can disproportionately affect women and girls, who may experience long-term declines in human and financial capital if they forego school or income-generating activities (Chant & McIlwaine, 2015). Inadequate WASH can also imperil women and girls’ dignity and self-respect while increasing their feelings of shame and humiliation (Chant & McIlwaine, 2015; Massey, 2011). More positively, providing WASH in informal settlements can help reduce women and girls’ time burdens, as well as reduce stress (see Parikh et al., 2015, for Ahmedabad). Before upgrading in Ahmedabad, women averaged as much as 2 hours per day collecting water, but afterward used the time saved for livelihoods, housework, or leisure (Parikh et al., 2015). In Kibera, one of Nairobi’s largest informal settlements, residents said that a new toilet block increased their social standing and sense of dignity: “We are proud to invite friends and family now” (quoted in Joshi et al., 2011, p. 105).

Diverse Forms of Upgrading

Examples of what could be termed informal settlements’ “upgrading programs” date back to the early 20th century. But it was in the 1960s that these came to be seen as a significant type of intervention. Inspired by the work and writings of William Mangin (1967) and John F. C. Turner (1967, 1968, 1976) and by changes in government policies by the Peruvian government, a new approach was developed, centering on supporting what came to be termed slum or informal settlement “upgrading.” In 1969, the “Kampung Improvement Programme” received support from the Indonesian government and the World Bank in Jakarta (and later many other cities). This approach was then adopted by many city and national governments and some international agencies looking for more effective ways of addressing the housing needs of those living in informal settlements. Many recognized that conventional responses were not working and were even making conditions worse by large-scale bulldozing.

Upgrading seeks to improve housing and living conditions by providing basic infrastructure (typically piped water, sanitation, and connection to drainage networks and electricity) and services (solid waste collection and sometimes healthcare and schools), supporting the upgrading of houses—and for some providing legal land tenure and a legal address (Massachusetts Institute of Technology, 1999–2001).

Informal settlements are diverse in what they need from upgrading, what is done (or not done), and how upgrading initiatives are shaped by politics, including government-inhabitant and government-community relations, as well as by how land tenure and, where needed, tenant–landlord issues are resolved (Weru, 2004). Urban settlements in need of upgrading range from irregular land subdivisions that are already in conventional grids and only require legalization and housing improvements (Hasan, 2006), to informal settlements that lack basic infrastructure, services, and addresses and may be located in sites that are difficult to upgrade. There is also diversity in how much upgrading costs per household served, and who pays (see Almansi, 2009). There is also the issue of changes in costs for services: Do upgraded households face difficulties affording payments for water and other services that must be paid for, or is this less expensive than in the previous informal provision (Mitlin et al., 2019)? In this article, many of the case studies on upgrading kept down costs to ensure they could be afforded (Delgado et al., 2020; Hasan, 2006). Informal settlement residents are often paying such a high price in time and money for water that upgrading can provide much improved provision without increasing costs.

The diversity of approaches to upgrading is well illustrated by an assessment of 11 housing projects supported by the Indian government’s Basic Services for the Urban Poor program. Patel’s (2013) assessment, “Upgrade, Rehouse or Resettle?,” showed how initiatives titled “upgrading” ended up displacing the original inhabitants. Many of the BSUP projects were simply public housing construction relabeled—and often with very inadequate provision for the “basic services” whose improvement is meant to be at the center of the BSUP (Patel, 2013).

In terms of who initiated the upgrading initiative, this can be national or state government, municipal authorities, grassroots organizations (that include low-income residents), local and international nongovernmental organizations (NGOs), and official development assistance agencies.

In Latin America, many of the most interesting and successful upgrading programs have been led by local governments (Rojas, 2010; Sette Whitaker Ferreira et al., 2020). By contrast, in Africa and Asia, many of these have been led by community organizations working with city governments. This growing role of grassroots organizations is supported by the network of which they are part: Slum/Shack Dwellers International (SDI, 2016), a network of community-based organizations and federations of the urban poor in 32 countries and active in hundreds of cities and towns across Africa, Asia, and Latin America. Upgrading (and gathering the data needed to implement these) is one of their main activities (see, e.g., Chitekwe-Biti et al., 2012; Livengood & Kunte, 2012). The federations’ foundation is community-managed savings groups; most savers and savings managers are women (d’Cruz & Mudimu, 2013).

Table 1 lists the different forms that informal settlement upgrading has taken and what they involve in terms of water and sanitation and government engagement with those to be upgraded.

Table 1. Different Forms of Informal Settlement Upgrading

Forms of Upgrading

What it Involves

Government Engagement with those to be Upgraded

Upgrading that is actually eviction

Pushing residents out of their homes and settlement and rebuilding, but with residents not able to access “upgraded” dwellings (see Patel, 2013)

Directed by government, usually implemented by contractors

Rudimentary upgrading

Some very basic interventions—e.g., community taps and public toilets

Directed by government, usually implemented by contractors and usually with inadequate maintenance

More complete upgrading

Piped water and toilets in each home, electricity, some re-blocking, paved access roads, sometimes sewers and drains. Little consultation with residents.

Planned and managed by government agencies and mostly implemented by contractors; often a lack of maintenance for infrastructure

Comprehensive upgrading

Legal land title, full range of infrastructure and services (including neighborhood level such as drainage, street lighting, and solid waste collection), support for housebuilding and improvement and for enterprises. Consultation with residents.

Strong government commitment to this, but planned and managed by government agencies and mostly implemented by contractors. The settlement becomes “formal” in the sense that it is served by city authorities for policing, street lighting, solid waste collection, and other public services.

Comprehensive community-led upgrading

As above, but with community control as exemplified in upgrading programs supported by CODI and SDI affiliates.

Strong government support for community organizations.

Comprehensive community-led upgrading with resilience lens

As above, but with greater attention to assessing and anticipating future risk levels.

Strong community-local government partnership.

Transformative upgrading

As above, with attention to low carbon footprint added.

Strong community-local government partnership; support from national government.

This is a text that has been developed over time; an earlier version is in Satterthwaite et al. (2020).

Of course, on the ground, there are huge variations in how much of what is needed is actually provided and the quality of provision. Success with upgrading water and sanitation provision also depends on making the right choice for each specific context or location on water and sanitation technologies. High densities and small plot sizes limit possibilities for on-site sanitation (Satterthwaite et al., 2019). Infrastructure maintenance is often problematic, as few municipal authorities take responsibility for this in upgraded settlements. This variation also means very large variations in how much upgrading contributes to improving residents’ health. Where the full range of improvements are made, these can include improvements in many of the social (and other) determinants of health (see “Upgrading and Implications for Health”).

Water, Sanitation, and Upgrading Informal Settlements

There are many case studies of informal settlements discussing changes in WASH provision after upgrading interventions. For instance, after water, sanitation, roads, and electricity were provided in Chaisa, Zambia, there was a rise in home-based enterprises, with benefits for poverty reduction and gender equality, as women predominated among these enterprises (Mpembamoto et al., 2017). The case studies of informal settlement upgrading show a great range in what is done and by whom—from rudimentary to comprehensive; from citizen or community driven to local government provision, to co-production (Mitlin, 2008). Table 1 highlights this. Then there are government initiatives to improve water and sanitation in informal settlements that do not get seen as upgrading, but are instead just the normal functioning of local or national government.

Comprehensive upgrading needs a lot of management that is accepted by the population. For instance, residents may have rival claims to the same land plot, or where boundaries are; local elites may also try to benefit from data-collection and upgrading initiatives (Rigon, 2017). Re-blocking—adjusting plot and site boundaries to allow access roads and water mains, sewers, and drains—can be contentious (no one wants to lose space) and costly if going down formal routes (e.g., legal costs for those wanting ownership or tenure). But community-driven mapping and enumerations have long been shown to be far quicker, cheaper, and more accurate than data collected by professionals or compiled by local government. Community-driven upgrading has also shown how agreement on re-blocking can be negotiated.

Upgrading may be among the most common means by which provision for water and sanitation is improved in informal settlements—and in some nations or cities, improvements provided at scale too. There are successes both for upgrading schemes planned and managed by local governments and those organized and driven by community organizations—although successful community-driven upgrading usually brings in local government to work in partnership (see Chitekwe-Biti et al., 2012; Fieuw & Hendler, 2017). Typically, successful upgrading schemes provide water piped to each home. They often include a private toilet in each home connected to a sewer, or services to support septic tanks or other forms of on-site sanitation.

There are also upgrading schemes with more modest improvements in water and sanitation that were important improvements and demonstrations of what was possible when budgets were constrained.

Upgrading can also build or strengthen community organizations in the settlement to be upgraded, and build good relations with local government and (where relevant) utility companies. An example of this is the upgrading program in Freedom Square, an informal settlement in Gobabis, Namibia, with 4,173 inhabitants on a 60-hectare site (Delgado et al., 2020). This upgrading program is also notable for keeping down costs. The upgrading costs were about one fifth those of conventional approaches, and the good relations with local government allowed lower (cheaper) standards. It is also a demonstration of what community-driven upgrading can do when budgets are constrained. The upgrading also received national government support. This and other initiatives by the Shack Dwellers Federation of Namibia, working with a support NGO (the Namibian Housing Action Group) and municipal authorities, show how it is not so much in what was done, but in how it was done and financed, including the pivotal role of inclusive partnerships between local government and the Namibian Federation (Delgado et al., 2020).

As suggested above, upgrading can also involve re-blocking that supports improved water and sanitation. Re-blocking may be needed to rearrange plots so as to secure regularization of titles and provide space for pipes and access roads.

High-quality upgrading requires access to larger, formal infrastructure networks (water mains, sewer systems, drains, roads, electricity); most informal settlements have too high a population density for on-site sanitation to work well (Satterthwaite et al., 2019). In Pakistan, the much studied and copied methodology of the Orangi Pilot Project—Research and Training Institute (OPP-RTI) for greatly extending high-quality water and sanitation provision has enabled households and community members to build the “small” pipes, which are then integrated into the official water and sanitation infrastructure (the big pipes) (Hasan, 2006). Other community-driven upgrading programs, such as the hundreds supported by Thailand’s Community Organizations Development Institute (CODI), provide connections to the formal government system for water and sanitation as part of the upgrading initiative (Boonyabancha & Kerr, 2018).

However, upgrading programs may not have government infrastructure networks into which they can readily fit. Autonomous or semi-autonomous systems must then be sought. But these are often problematic in informal settlements, especially large and high-density settlements. In Mukuru, one of Nairobi’s largest informal settlements, the Kenyan Homeless Peoples Federation is developing an upgrading program with other stakeholders (Muungano wa Wanavijiji, 2018). It is insisting on sewers, having seen the ineffective nature of most non-sewered sanitation systems in large and high-density informal settlements (Lines & Makau, 2018).

Upgrading and Implications for Health

Few other measures have greater potential to transform the well-being of the urban poor than participatory, integrated slum-upgrading programs and policies. However, the health equity benefits of slum upgrading are rarely acknowledged … or analysed as part of project and policy impact evaluations.

(Corburn & Sverdlik, 2016)

Given this and the fact that “slum” upgrading has become a conventional government response to informal settlements in many countries, and given how the main justification for it is often improved health, why is there so little research on this? Perhaps this gap is in part because of the lack of coordination between the government bodies responsible for upgrading and for health. In part, it may reflect the astonishing lack of official data on household and community health and on the physical and social determinants of health in informal settlements that could provide some baseline (Satterthwaite et al., 2019). In part, it suggests the implementing agencies’ lack of interest in relevant data collection for health impact assessments; there are already various complexities of getting an upgrading program designed, funded, and implemented, with coordination needed across different government departments. And for international funders, there is pressure to implement rapidly. So, for many reasons, gathering such data is not seen as a priority. There are also logistical and security difficulties facing researchers in working in informal settlements, for which there are no maps and street names and in which they may face hostility. Finally, upgrading projects often have many components that make it difficult to identify the most important for health impacts.

This article has drawn on three papers that recently reviewed a range of slum or informal settlement upgrading initiatives and analyzed how health issues were treated. Two are systematic reviews, including Henson et al. (2020) on “evaluating the health effects of place-based slum upgrading physical environment interventions.” It covers 2012–2018 and also considers the findings of another systematic review of the literature on this topic that covers between 1986 and 2012 (Turley et al., 2013). The third is Corburn and Sverdlik (2016) that reviews how health issues are addressed in the documentation on 18 urban slum-upgrading projects or program. This book chapter “focused on slum-upgrading projects self-described as ‘integrated’ and multisectoral, since [their] hypothesis was that these, as opposed to more narrowly defined projects, would result in the greatest health benefits for the urban poor” (p. x). There is some overlap in the upgrading initiatives reviewed by Henson et al. (2020) (that includes those in Turley et al. [2013] and Corburn and Sverdlik [2016]). But perhaps there is less duplication than might be anticipated; only 5 of the 18 case studies in Corburn and Sverdlik (2016) were in Henson et al. (2020). This highlights how the list of upgrading evaluations accepted for review is influenced by the use of different criteria for inclusion.

All three studies highlighted the lack of relevant literature. For instance, Henson et al. (2020) found that out of 5,901 studies identified through database searches, only 13 met the Review’s inclusion criteria. Findings were pooled with another 14 papers identified in Turley et al.’s (2013) systematic review. Henson et al. (2020) terms those that used a longitudinal study design as “primary” evaluations; of the thirteen evaluations published between 2012 and 2018, eight were primary. Henson et al. (2020) noted that all were based in Latin America. This is surprising given the vast number of upgrading initiatives in Africa and Asia and the very large and diverse literature on them (but such research has not typically looked at health aspects of upgrading).

For Henson et al. (2020), the criteria for a study’s inclusion were quite strict in regard to the study design and methodology3 but less so on what was being assessed—health outcomes or social, economic, and environmental outcomes stated as health-relevant by evaluation authors. Some of the studies included would not typically be considered upgrading—for instance, they included evaluations of initiatives solely providing public transport or street paving. Many of the 27 evaluations did not measure health outcomes; instead they measured changes in one or more determinants of health, such as changes in property prices or health insurance claims. Perhaps there is some bias toward researching those determinants that are relatively easy for researchers to measure?

The review by Turley et al. (2013) found a small number of evaluations across the period of 1986–2012 and concluded that heterogeneity and evidence gaps prevented strong conclusions regarding the effect of physical environment upgrading on health and well-being. The review by Henson et al. (2020) similarly noted how the breadth of intervention types and contexts, as well as study designs and study quality, presented challenges in synthesizing the evidence from these interventions. Health-related outcomes from primary and supporting evaluations included in Henson et al. (2020) (from the most to the least commonly assessed) were communicable disease, personal or neighborhood safety, social capital, quality of life, general mental health, general physical health, mortality, nutritional deficiencies, injuries, and non-communicable diseases. Overall, comprehensive interventions had largely non-statistically significant findings.

Henson et al. (2020) also noted that some important types of interventions were not evaluated in the studies reviewed, including upgrading related solely to water supply and sanitation infrastructure.

To help fill existing gaps, Henson et al. (2020) suggest that “primary data collection can be efficiently complemented using secondary data sources (e.g., census data, hospital data, mortality records) that may contain data on outcomes, denominators, or health determinants for the intervention and control groups at multiple time points.” But it is rare to have a census authority that is prepared to provide local authorities (and researchers) with census data disaggregated to streets or particular settlements. Household surveys have too small a sample size to be able to provide data for streets, settlements, and wards. Records from hospitals and health centers are generally only available on paper and often incomplete (see Brown, 2020). Causes of death with details of age and home location are often incomplete and do not cover the whole city. So, there is a major shortfall in detailed, comparable data on illness, injury or premature death or on other aspects of health and health determinants for informal settlement residents (Dodman et al., 2019).

For the 18 “slum upgrading” initiatives reviewed in Corburn and Sverdlik (2016), most evaluations examined the impacts on shelter conditions and infrastructure; health “co-benefits” were rarely acknowledged. Only 10 explicitly mentioned health impacts and of these, only two measured specific diseases. Of all the evaluations that mentioned health, only self-reported data were gathered. Thirteen of the evaluations directly mentioned potential social determinants of health, such as reduced water collection times, sense of pride and happiness, and women’s increased empowerment, though none of the reports explicitly framed these issues as important influences on population health. Corburn and Sverdlik (2016) suggest that their review reflected the following challenges for understanding health equity:

Measures of health were very limited and tended to focus on childhood mortality or morbidity (particularly due to diarrheal or other communicable illnesses).

Economic impacts including reduced costs for water were widely discussed—but rarely by assessing how infrastructure improvements changed pathogenic exposures, safety, or gender equity.

Several of the case studies highlighted promising practices of community-led upgrading, but the reports did not link participation, empowerment, or self-efficacy to population health.

To give an example of an assessment of “comprehensive” upgrading (and also included in Turley et al., 2013), Soares and Soares (2005) looked at “The Socio-Economic Impact of Favela-Bairro: What Do the Data Say?” Despite its title, this paper also considers in detail the health impacts of Favela-Bairro in Rio de Janeiro, one of the largest and best-known upgrading programs. The paper highlights the improvements the program brought to informal settlements including enhanced coverage of water, sewerage and rubbish collection. It also highlights the value and the limitations in drawing on census data and data on causes of death certificates. The study concludes with the comment that the data available was inadequate to answer many of the fundamental evaluative questions—including those linked to health impacts.

Henson et al. (2020) includes a discussion of the difficulties facing any researcher seeking to work on health issues in informal settlements. These key challenges include the following:

Mobility: “For designs with data collected over time, consistent use of the same validated measures on individuals will give the clearest picture of problems.” But many informal settlements have constant population movements in and out—and perhaps especially where much of the housing is rented.

Data: The lack of data on health status and health outcomes and of the large range of social, physical, economic and political determinants of health in informal settlements. There are also the difficulties facing outsiders in doing primary research in informal settlements, which may include hostility from residents or vested interests and a lack of maps and street addresses.

Henson et al. (2020) also note some knowledge gaps including attention to social, legal, and economic interventions in upgrading. Evidence of positive health effects, including those of housing on quality of life and communicable diseases, provides only limited insight as to which specific pathways contributed to health benefits of such interventions.

What this also misses is the experience with community-led mapping, profiling or enumerating informal settlement to support and inform upgrading. As discussed below, there are alternative approaches to gathering data and co-creating inclusive upgrading interventions with residents of informal settlements.

Engaging Government and Community Organizations

All the large-scale examples of upgrading have engaged with local government even if local governments’ role varied enormously. In Latin America, it was common for municipal authorities to design and lead the upgrading schemes although in consultation with the residents (often linked to participatory budgeting—see Cabannes, 2015). This reflects the political changes that strengthened Latin American city governments and introduced elected mayors and city governments (Goldfrank, 2011; López Follegatti, 1999). It also reflected larger municipal budgets (United Cities and Local Governments [UCLG], 2014). Meanwhile, in sub-Saharan Africa and Asia, it is more common to see active grassroots organizations and federations, in which community organizations from the settlements to be upgraded take the lead and serve as key implementers.

There are many case studies of upgrading and improved water and sanitation in informal settlements coming from initiatives led by grassroots organizations and their federations. There are several valuable examples from Slum/Shack Dwellers International (SDI).4 Among federations that are SDI affiliates, there is a different attitude to data on water and sanitation (and other key needs): Low-income residents themselves design and implement very detailed surveys and maps covering all houses and households—which they use subsequently to guide the planning and implementation of upgrading. These community-led data-collection initiatives can be as detailed as Demographic and Health Surveys on provision for water and sanitation, but they cover everyone (not just a small sample) and include data on many social (and other) determinants of health. These findings then provide the basis for developing water and sanitation systems that can reach all households. To date, SDI’s local federations have mapped and surveyed over 460 cities.

To give an example of the depth and detail of SDI’s data, in Kisumu (Kenya), grassroots profiles of each of the city’s 28 informal settlements reported on the quality and extent of provision for water and sanitation and other infrastructure and services. The collection of this data than provides the basis for discussions as to residents’ priorities for interventions. The Slum Dwellers Federation of Kenya—Muungano wa Wanavijiji—profiled nearly 221,000 residents in Kisumu’s informal settlements, where three quarters of residents lived on dangerous sites, including flood-prone areas or nearby garbage dumps. Most residents were tenants, and 83% lived in temporary structures; minimal services, major infrastructure deficits, and poor access to health facilities only compounded the risks facing these residents. An estimated 69% of residents lacked regular water supplies, and in 20 settlements there were over 100 residents per working toilet. Regular garbage collection was almost nonexistent. Because only 11 settlements had a health clinic inside, many residents were forced to walk long distances to clinics (posing major challenges for pregnant women). Residents consistently prioritized improving water drainage and sanitation and sewage, with a few areas also prioritizing electricity and land tenure (see also Satterthwaite et al., 2019).

The questions asked in Kisumu (and other SDI enumerations) have covered a great range of health determinants. For water, questions were asked about the household’s main water sources (nine possibilities); number of individual, community, and shared taps; functionality and water quality; and who supplies the taps. On average, what do households spend on water per month? Additionally, the enumerations indicate how long it takes a household to collect water; how many hours per day water is available; whether a settlement is connected to a main water pipeline; and general comments about water. For sanitation, questions included whether the settlement is connected to a sewer; whether people pay for using toilets (average paid per month); what is the mix of toilet types; number of public toilets and management; and average waiting time for a toilet.

Among other topics covered in SDI’s data are the following:

Land ownership and history for each informal settlement

Demographic and structure details



Garbage collection







Commercial establishments and other services and establishments such as playgrounds, banks, informal markets, fire and police stations, mosques, temples, and churches

Organizations: community leaders and their roles

Community priorities: Discussions of upgrading make the distinction between community-driven and municipal-driven upgrading initiatives, but many of the largest and most successful initiatives came out of partnerships between these. In the upgrading in Gobabis described in “Upgrading and Implications for Health,” good relations with city and national governments allowed the Namibian Federation to get their agreement on changing building, land, and infrastructure standards to lower the costs (allowing cheaper serviced plots) (Delgado et al., 2020).

As noted in “Water and Sanitation in Informal Settlements,” the Research and Training Institute of the Orangi Pilot Project (OPP) in Pakistan provides support for upgrading, sanitation, storm drains, and toilets. Notable for its scale and its clever combination of household, community, and government funding, it produces high-quality sanitation at costs that low-income households can afford. It has integrated the household and community sanitation infrastructure into the government-provided main networks. It also supports many other initiatives that can be considered part of upgrading (Hasan, 2006).

One of the most ambitious, ongoing upgrading programs is in Mukuru, one of Nairobi’s largest informal settlements. It is led by the Kenyan Homeless People’s Federation (Muungano wa Wanavijiji). What makes it unusual is the government supporting this community-led process, its scale (around 100,000 households), and its engagement with all stakeholders seeking to generate consensus (Lines & Makau, 2018; Sverdlik et al., 2020). The Kenyan Federation also receives financial and technical support from the Akiba Mashinani Trust, including a range of financial services and support for grassroots savings groups; loans for livelihoods; and community project loans (for Muungano’s social housing, sanitation, and basic infrastructure projects) (Weru et al., 2018).

The Community Organizations Development Institute (CODI) in Thailand is unique as a national government agency that supports community-driven upgrading all over the country. It funds and supports community organizations formed by the inhabitants of informal settlements to plan and manage upgrading their settlement. The upgrading includes connection to the city’s water supply and drains. The upgrading also supports them to buy or lease the land they are on—and if this is not possible, CODI supports them to find and develop another site. More than 100,000 households have benefitted from this program and the improvements in water and sanitation. This is another example of an initiative that includes much improved provision for water and sanitation but would never be seen as a water and sanitation initiative (Boonyabancha & Kerr, 2018). The strong support for communities’ initiatives also brings a range of other health benefits, for example, social cohesion and ensuring support for the disabled and elderly (Colenbrander & Archer, 2016).

The South African government has made a strong commitment to stop building houses for low-income-groups in poorly located land and to shift more resources to upgrading informal settlements provided that they are in areas close to jobs (South African SDI Alliance, 2013). The government has also made a strong commitment to community-led practices for upgrading. But, as discussed in South African SDI Alliance (2013), Fieuw and Mitlin (2018), and Fieuw and Hendler (2017), it has proved difficult to translate these commitments into practice on the ground.


Upgrading initiatives in informal settlements are much influenced by the relationships between informal settlement dwellers (and their community organizations) and local government (politicians and key departments). Comprehensive upgrading (see Table 1) has to draw in different government departments—for instance in providing or improving access to government schools and healthcare. The relationship with official agencies or utilities responsible for water, sanitation, and drainage will influence if, when, where, and how informal settlement dwellers get included in the formal urban systems or supported to develop their own systems.

Many upgrading programs have helped develop more productive and supportive relations with local government, which then laid the basis for addressing water and sanitation and increasing the scale and scope of what is done. Upgraded settlements also need support to maintain the infrastructure and services, and this too benefits from good community–local government relationships. It is also this good relationship with local government that allows some reduction in standards that lowers the cost of housing—for instance smaller plot sizes and lower infrastructure standards.

Of course, the relationships between grassroots organizations and government are shaped by how these organizations view government. One of the key principles of the slum/shack dwellers federations is that they offer their resources and capacities to local government. This article has included examples of this, including the community-managed surveys, enumerations, and mapping that upgrading plans need. As the example from Kisumu made clear, these community-driven data-collection processes also provide a wealth of data about health and its social, environmental, and political determinants.

Community-driven processes can deal with issues that are far more difficult for professionals to resolve. There are many challenging or contentious issues in upgrading that need the informal settlement’s community organizations to build agreement—for instance re-blocking, who gets tenure of each plot, and how tenants’ needs are addressed.

This article has stressed the great variety in the quality of provision and maintenance for water and sanitation within upgrading programs.

See the contrast noted earlier between most upgrading in Latin American cities, which is driven by the municipal government, working wherever possible with local civil society organizations, and in sub-Saharan Africa and Asia, where grassroots organizations and federations have led in many instances and collected the required data.

At the same time, community organizations cannot build the big infrastructure (water treatment plants, water and sewer mains, and sewage treatment plant), but they can provide the taps and toilets in their homes and the water and sewer pipes at the neighborhood or lane scale that connect with the big infrastructure (see examples of OPP and CODI given herein).

There are so many economic, social, political, environmental, and other factors (including behavioral factors) that influence health in informal settlements that it is difficult to isolate the impact of one from all the others. Many factors are also difficult to measure. Climate change–related factors and their future trajectories also need to be included (Satterthwaite et al., 2020). And, of course, COVID-19 has imposed heavy health, economic, and social burdens in informal settlements, with major potential to exacerbate urban health inequalities (Corburn et al., 2020; Wilkinson, 2020).

Much of upgrading’s support for water and sanitation goes uncounted in government water and sanitation statistics. There is also a lack of basic data about informal settlements both in terms of the health of their inhabitants and the social, economic, political, and environmental determinants. And most governments do not collect data on informal settlements—so the UN is also unable to provide global overviews of their scale and rate of change, as they do for slums.

But if one asks what data is for and considers its strong potential to drive improvements in water and sanitation, then community-led data-gathering processes can provide a very rich understanding of how the quality of provision for infrastructure and services has changed or can change. Such community data-collection processes also, crucially, engage local residents in the prioritization and implementation of interventions, often in partnership with local officials (Lines & Makau, 2018; Patel et al., 2012). In turn, residents’ health issues and priorities can be equitably represented and acted on in community-led initiatives, with the potential to enhance the social, political, and environmental determinants of health in informal settlements.

Further Reading

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Two books on life in informal settlements give powerful examples of contexts where the inhabitants struggle to get upgrading and basic services. Vooks listed above by Moser and by Perlman.


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  • 1. According to UN data for SDG 11 (“Make cities inclusive, safe, resilient and sustainable”), an estimated “828 million people live in slums today” (United Nations, n.d.).

  • 2. See Ray (2007), Burt et al. (2016), and Tilley et al. (2013) for discussions of gender and WASH; Carrard et al. (2013) provide a gender-sensitive framework to evaluate WASH project outcomes.

  • 3. In particular, they used a randomized control trial (RCT), controlled before-after (CBA), interrupted time series (ITS), uncontrolled before-after (UBA), or controlled post-intervention (CPI) study design with at least 100 observations.

  • 4. See endnote 1 above.