January 2022

Willingness-to-pay for the “NuPump” Inline Handpump Chlorinator


Almost half of the population (40%) in sub-Saharan Africa rely on handpumps for drinking water. However, 25% – 50% of these handpumps have detectable levels of fecal indicator bacteria (e.g., Escherichiacoli). Additionally, water stored in the household often has higher contamination levels because of further contamination during transport and storage.

Chlorination at the handpump inactivates microorganisms initially present in groundwater and provides a chlorine residual that reduces the risk of additional contamination during transport and storage. Water4 has developed the NuPump, an inline handpump chlorinator that relies on a solid chlorine cartridge to treat water as it gets pumped. The NuPump also includes a filter to ensure that chlorine chips coming off the cartridge or solid particles coming from groundwater, such as iron precipitates, are not present in the outflow water. This study evaluated household willingness-to-pay (WTP) for the NuPump inline handpump chlorinator in rural Ghana.



The communities in our study area were small, with an average of 16 households. Across all communities, most households (69%) reported contributing 2 GHS per month for the NUMA program, which provides regular handpump maintenance services. The mean payment was 1.9 GHS. Accordingly, an average community with 16 households would be paying approximately 30 GHS per month for maintenance of the handpump.

Although most households reported paying 2 GHS per month, several (22%) reported not currently contributing any amount to help pay for the NUMA program. A few others reported paying more to ensure that the program continued despite these non-paying households. In one extreme case, a single household reported paying 40 GHS per month, because that household was the only one regularly using the NUMA handpump in the community. In some communities (~40%), handpump caretakers strictly enforced payments by allowing only households that have paid their monthly subscription to use the handpump. In such instances, households that were late in their payment had to rely on alternative water sources (e.g., other handpumps or surface water).


According to the double-bound dichotomous choice method

With the double-bound method, we found that 82% of households would be willing to pay at least GHS in addition to their current NUMA contribution. The average household was willing to pay approximately 2 GHS for chlorination, essentially doubling their existing NUMA payment. However, WTP declined considerably above this level of 2 GHS; for example, only 13% of respondents were willing to pay 4 GHS on top of their current payment. Households in treatment communities tended to exhibit lower WTP for chlorination than those in control communities (p=0.02). On average, WTP in treatment communities (where the NuPump chlorinator was already installed) was 0.6 GHS less than in control communities when accounting for other factors also influencing WTP (including wealth, respondent gender, and whether the household used the NUMA handpump as their primary water source). Interviews with community members and handpump caretakers suggested that households in control communities may have
expected the installation of the chlorinator to solve all existing issues with their handpumps, while the experiences of households in treatment communities showed that the NuPump could introduce additional challenges while not addressing all existing concerns.

Specifically, households in treatment communities noticed that the NuPump reduced the handpump’s flow rate and some did not like the smell of chlorine coming from the water. Additionally, community members had hoped that the NuPump chlorinator would solve issues related to the water’s aesthetic quality (e.g., a salty taste), but these challenges persisted after installation, causing these households to realize that the chlorinator cannot address some key concerns.

According to discrete choice experiments

On average, WTP for handpump chlorination estimated with the DCE method was 2.2 GHS per month, quite similar to the estimate obtained from the double-bound method (1.9 GHS/month). However, the DCE method estimated that only 66% of households would be willing to pay at least 1 GHS per month (compared with 82% with the
double-bound method). The DCE method also identified that treatment households exhibited lower WTP than control households (p<0.001), and the estimated difference between the two groups (1.6 GHS per month less among treatment households) was more pronounced than what was found through the double-bound method,
reinforcing the idea that households in treatment and control groups have different conceptions of the benefits and drawbacks of the NuPump chlorinator.

Read More

post end icon

Join our newsletter

Quality insights, straight to your inbox.