Subsidies for faecal sludge emptying: lessons from Kampala and Lusaka

Contributed by Kun Zhang (Athena Infonomics), Pride Kafwembe (Lusaka Water Supply and Sanitation Company–LWSC), Kapanda Kapanda (LWSC), Evans Mambwe (LWSC), Julian Musiime (Kampala Capital City Authority–KCCA), Eunice Gnay Namirembe (KCCA), Allan Nkurunziza (KCCA), Annabella Nyakaisik (Athena Infonomics)

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Globally, most cities in low-income countries have limited or no access to centralized sewers. Households in these cities, especially those living in Low-Income Settlements (LISs), have a high degree of reliance on On-Site Sanitation (OSS) systems– septic tanks or pit latrines, which require periodic emptying to function properly. However, due to the high cost of emptying, many OSS may only get emptied once in 5–10 years as opposed to the recommended once in 2–3 years, or are simply abandoned when full, posing risks to public health and the environment. The emptying market is also often underdeveloped and dominated by informal service providers.

To address the issues of low demand for emptying and unsafe emptying practices, the cities of Kampala and Lusaka have experimented with subsidy models for faecal sludge emptying. Kampala piloted a voucher-based subsidy that targeted the most vulnerable households, whereas Lusaka adopted a self-selected targeting approach aimed at increasing overall emptying demand while gradually phasing out the subsidy. This case study describes the two models, the context for their design, how each model is influencing emptying outcomes and the lessons learned.

Date of publication: September 2022

Geographic information



City and population:

Kampala: 1,600,000
Zambia: 2,600,000


  • Kampala and Lusaka are large capital cities in Sub-Saharan Africa with at least 60–70% of their population living in Low Income Settlements (LISs), where the predominant form of sanitation access is OSS facilities that need periodic emptying for environmental and public health safety.
  • Due to the high cost of pit emptying, households traditionally abandon pits when full. However, this practice is no longer feasible in densely populated areas due to space constraints. Many households have thus turned to informal pit emptying services which are unsafe.
  • Lack of formalized emptying services in LISs further creates challenges around service quality and unsafe practices, such as illegal dumping.


  • Lusaka and Kampala have chosen to tackle the emptying challenges through contracting models with subsidies. Kampala offers a voucher-based subsidy that targets the most vulnerable households, whereas Lusaka provides a blanket volumetric subsidy for all eligible households (residing in LISs and using pit latrines) through performance-based contracting of service providers. These models are meant to address the emptying issues by increasing demand and affordability for emptying, while formalizing the emptying market to ensure service quality and safety.

1. The Problem

Kampala and Lusaka are big capital cities in Sub-Saharan Africa with more than half of their population living in LISs, which are densely populated and unplanned informal settlements with limited access to sanitation services. The predominant form of sanitation access in these LISs is pit latrines, many of which are unlined or partially lined pits, as they are more affordable than septic tanks. Table 1 summarizes the basic sanitation scenario in these two cities.

Some of the major sanitation challenges in these LISs, especially around faecal sludge emptying, include high number of households sharing a toilet and poor toilet standards and designs. The high frequency of use results in toilets filling up quickly; however, households are often unwilling or unable to pay for emptying services, and many of the pit latrines in LISs are inaccessible by emptying services due to narrow streets. Moreover, the increasing space constraint in the LISs means that it is becoming less feasible to abandon pits when they are full.

The difficulty of emptying in LISs is further exacerbated by the high cost of pit emptying and the lack of formalized services in LISs. Compared to septic tank emptying, pit latrine emptying tends to be more expensive due to the higher labour intensity, as the faecal sludge content of pits is usually more concentrated with less water content and unsuited for removal through vacuum trucks. Many households hence construct very large pits that take a long time to fill up and engage informal emptiers when the pits are full. Informal services are often associated with poor service quality and unsafe practices such as illegal dumping. Hence, the cities need to increase demand and affordability for emptying while formalizing the emptying market to ensure service quality and safety.

2. The solution

Table 2 summarizes the different emptying subsidy models developed by Kampala and Lusaka. Kampala started the programme during the COVID-19 pandemic as an emergency emptying initiative to control the potential spread of viruses through human waste, and the programme evolved through the seven rounds of emptying to date. On the other hand, the programme in Lusaka has been operating continuously under the same overall design, enabled by a dedicated donor grant budgeted for 2.5 years of programme costs. In both cities, the contractors receive the subsidy from the city government/utility upon satisfactory completion of the services.

At least 92% of the targeted beneficiaries in Kampala benefited from the subsidies. The shortfall was largely attributable to households misplacing the vouchers given to them and hence unable to schedule the service. This was ameliorated in later rounds due to the shift from a paperbased voucher system to a digital platform. Lusaka has achieved its target of emptying 12,800 toilets by the first quarter of 2022. Figure 3 shows manual pit emptying (using a pitvaq emptying equipment) service provider in Lusaka.

3. Lessons Learned

Kampala’s voucher system benefited the most vulnerable households in dire need of emptying, whereas Lusaka’s broad eligibility criteria encouraged more households to avail the subsidy and was able to achieve some level of economies of scale. As both cities used the ownership of formal licenses as an eligibility criterion for service providers to bid for the contracts, more emptying companies have been seen to make efforts towards formalization. Meanwhile, both cities shared a set of challenges while implementing their programmes, including costing underestimates by service providers, payment delays by service authorities due to issues such as bureaucracy and structural concerns regarding unlined pit latrines which collapse easily during emptying. Even though unlined pits are cheaper to construct, the overall cost over a period would be higher for substandard pits because they collapse. This raises a set of important questions – is emptying for the poorest always valuable if the pit has a high risk of collapsing? How do we connect emptying subsidy to OSS upgrades to maximize benefits for the poor and cost effectiveness? Both Kampala and Lusaka have also been working to establish OSS standards and upgrade substandard systems, and their lessons may be valuable for policymakers.

About us

About the institution / organisation

Kampala Capital City Authority (KCCA) is the local government of the City of Kampala in Uganda.

Water for People (WfP) is a global non-profit helping improve access to clean water and sanitation, subcontracted by KCCA to implement the programme.

Lusaka Water Supply and Sanitation Company (LWSC) is the water and sanitation utility operating in Lusaka Province, Zambia.

Monitoring, Learning and Evidence (MLE) partner: Athena Infonomics is a data-driven global consultancy, supporting eight cities in Sub-Saharan Africa and South Asia in their Citywide Inclusive Sanitation programmes.