The Aquaya publication Measuring the Impacts of Water Safety Plans in the Asia-Pacific Region has been featured in the MDPI Special Issue reprint book of “Drinking Water Quality and Human Health.” This book, edited by Patrick Levallois and Christina Villanueva Belmonte, is available for free to download.

Aquaya has contributed to a new publication available to the public, Associations between High Temperature, Heavy Rainfall, and Diarrhea among Young Children in Rural Tamil Nadu, India: A Prospective Cohort Study.




The effects of weather on diarrhea could influence the health impacts of climate change. Children have the highest diarrhea incidence, especially in India, where many lack safe water and sanitation.


In a prospective cohort of 1,284 children under 5 y of age from 900 households across 25 villages in rural Tamil Nadu, India, we examined whether high temperature and heavy rainfall was associated with increased all-cause diarrhea and water contamination.


Seven-day prevalence of diarrhea was assessed monthly for up to 12 visits from January 2008 to April 2009, and hydrogen sulfide (H2SH2S) presence in drinking water, a fecal contamination indicator, was tested in a subset of households. We estimated associations between temperature and rainfall exposures and diarrhea and H2SH2S using binomial regressions, adjusting for potential confounders, random effects for village, and autoregressive-1 error terms for study week.


There were 259 cases of diarrhea. The prevalence of diarrhea during the 7 d before visits was 2.95 times higher (95% CI: 1.99, 4.39) when mean temperature in the week before the 7-d recall was in the hottest versus the coolest quartile of weekly mean temperature during 1 December 2007 to 15 April 2009. Diarrhea prevalence was 1.50 times higher when the 3 weeks before the diarrhea recall period included 1d≥1d(vs. 0 d) with rainfall of >16.82mm>16.82mm (95% CI: 1.12, 2.02), and 2.60 times higher (95% CI: 1.55, 4.36) for heavy rain weeks following a 60-d dry period. The H2SH2S prevalence in household water was not associated with heavy rain prior to sample collection.


The results suggest that, in rural Tamil Nadu, heavy rainfall may wash pathogens that accumulate during dry weather into child contact. Higher temperatures were positively associated with diarrhea 1–3 weeks later. Our findings suggest that diarrhea morbidity could worsen under climate change without interventions to reduce enteric pathogen transmission through multiple pathways.

Aquaya Deputy Program Director, Dr. Jeff Albert, has co-authored an editorial in the American Journal of Tropical Medicine and Hygiene. It is publicly available, Community-Led Total Sanitation Moves the Needle on Ending Open Defecation in Zambia.

Aquaya has a new publication available to the public, “Are Presence/Absence Microbial Tests Appropriate for Monitoring Large Urban Water Supplies in Sub-Saharan Africa?”

Abstract: Screening for fecal contamination via microbial water quality monitoring is a critical component of safe drinking water provision and public health protection. Achieving adequate levels of microbial water quality testing, however, is a challenge in resource-limited settings. One strategy for addressing this challenge is to improve the efficiency of monitoring programs. In African countries, quantitative microbial testing methods are commonly used to monitor chlorinated piped water systems. However, presence/absence (P/A) tests may provide an appropriate alternative for water supplies that generally show negative fecal contamination results. This study compares 1048 water quality test results for samples collected from five African urban water systems. The operators of the systems conducted parallel tests on the 1048 samples using their standard quantitative methods (e.g., most probable number or membrane filtration) and the Colitag™ method in P/A format. Combined data demonstrates agreement rates of 97.9% (1024/1046) for detecting total coliforms and 97.8% (1025/1048) for detecting E. coli. We conclude that the P/A test offers advantages as a simpler and similarly sensitive measure of potential fecal contamination for large, urban chlorinated water systems. P/A tests may also offer a cost-effective alternative to quantitative methods, as they are quicker to perform and require less laboratory equipment.

Aquaya has a new publication available to the public, Cross-subsidies for improved sanitation in low income settlements: Assessing the willingness to pay of water utility customers in Kenyan cities.

Abstract: Most residents of the developing world do not have access to safely managed sanitation services, and large financial investments are required to address this need. Here we evaluate surcharges on water/sewerage tariffs as an option for supporting these investments in low-income neighborhoods. We investigated willingness-to-pay (WTP) for a pro-poor sanitation surcharge among customers of two urban water utilities in Kenya. Applying qualitative and quantitative methods, we conducted semi-structured in-depth interviews, focus-group discussions, and a double-bounded contingent valuation method for measuring WTP. We varied scenarios quasi-experimentally to study the effects of messaging and surcharge characteristics and evaluated factors associated with WTP. Our study finds that mean WTP was 290 KES (USD 2.9) per month, about 8% of the average water bill; median WTP was 100 KES (USD 1). In a multivariate analysis, WTP was significantly higher among customers that were younger, wealthier, shared toilets, and had higher water bills. WTP was also higher among customers that trusted the utility and distrusted the county government. Of our randomized scenarios, only the bill type was found to significantly influence WTP; WTP was higher if the surcharge was presented as a proportion of the customers’ last water bill vs a flat amount. Our findings suggest that in a sector that struggles to provide universal access to sanitation services, cross-subsidies may offer a means to support financing of safe sanitation for low-income households. These results indicate there are opportunities for cross-subsidies in urban Kenya that may be relevant for a wider understanding of surcharge payments that support basic services for low-income citizens.

Aquaya has studied and optimized water quality testing strategies in low-resource settings for over 10 years. We are happy to provide insights to help your organization develop or improve a monitoring program. Please reach out by contacting us.

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