There is still debate and uncertainty in the literature about the health benefits of community water supply
interventions. This paper reports on a changing incidence of self-reported diarrhoea associated with
the implementation of two community water supplies. We conducted prospective weekly recording of
diarrhoeal disease in three communities. Two of the communities were scheduled to receive an improved
water supply and one was expected to continue to rely on an unimproved source during the study period.
Data of self-reported diarrhoea was collected from each participating household on a weekly basis for up
to 56 weeks, of whichsome17 weeks were prior to implementation of thenewwater supply systems. Data
was modelled using Generalized Estimating Equations (GEE) to account for possible clustering within
households and within villages. For the two intervention communities in the study, the incidence rate
ratio (IRR) for all ages after the intervention was 0.43 (95% CI 0.24–0.79) when compared to the control
community (who did not receive an intervention), implying a 57% reduction of diarrhoea. Both of the
new water systems were unreliable, one not operating on 4 weeks and the other on 16 weeks. The more
reliable of the two intervention systems was also associated with less illness than in the least reliable
system (IRR = 0.41, 95% CI 0.21–0.80). We also noted anecdotal reports that during supply failures in
the new systems some people were starting to use household water treatment. The implementation of
improved water systems does appear to have been associated with a reduction of diarrhoeal disease in
the communities. However the health impact was most obvious in the community with the more reliable
system. Further research needs to be done to determine whether public health gains from community
water supply interventions can be leveraged by occasional use of household water treatment (HWT)
during supply failures.
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