Monitoring drinking water quality in nationally representative household surveys: cross-sectional analysis of 20 Multiple Indicator Cluster Surveys 2014-2019

Abstract

Background. The Sustainable Development Goals set an ambitious new benchmark for safely managed drinking water services (SMDW), but many countries lack data on the availability and quality of drinking water. Objectives. To quantify the availability and microbiological quality of drinking water, monitor SMDW and examine risk factors for E. coli contamination in 20 low-and middle-income countries. Methods. A new water quality module for household surveys was implemented in Multiple Indicator Cluster Surveys. Teams used portable equipment to measure E. coli at the point of collection (PoC, n=48323) and at the point of use (PoU, n=51345) and asked respondents about the availability and location of drinking water services. E. coli levels were classified into risk categories and SMDW was calculated at the household- and domain-levels. Multilevel modified Poisson regression was used to explore pre-selected risk factors for contamination. Results. E. coli contamination was commonly detected at PoC (range: 16- 90%) and was even more likely at PoU (range 20-97%). Coverage of SMDW was 56 % points lower than improved drinking water and water quality was the limiting factor for SMDW in 14 out of 20 countries. Detection of E. coli at PoC was associated with use of improved water sources (RR = 0.63 [0.54-0.75]) and accessibility on premises (RR = 0.81 [0.70-0.95]) but not with availability (RR = 0.94 [0.84-1.06]). Households in the richest quintile (RR = 0.67 [0.50-0.90]) and in communities with high (>75%) improved sanitation coverage (RR = 0.95 [0.92-0.99]) were less likely to use contaminated water at PoU whereas animal ownership (RR = 1.08 [1.03-1.14]) and rural residence (RR = 1.11 [1.04-1.18]) increased risk of contamination. Discussion. Water quality data can be reliably collected in household surveys and can be used to assess inequalities in service levels, to track the SDG indicator of safely managed drinking water services, and to examine risk factors for contamination. There is an urgent need to implement scalable and sustainable interventions to reduce exposure to faecal contamination through drinking water.

Invited Perspective: Beyond National Water Quality Surveys: Improving Water Quality Surveillance to Achieve Safe Drinking Water for All (Sustainable Development Goal 6.1)

“…Escherichia coli ( E. coli ) contamination is the primary reason safely managed drinking water criteria have not been met globally. This is a key finding of the new paper from the Joint Monitoring Program team ( Bain et al. 2021 ).…”

“…MICS water quality data are able to elucidate the situation in individual countries and, through the analysis by Bain et al. ( 2021 ), at an aggregate level. However, MICS water quality surveys do not provide the data that water managers need to inform improvements in water safety in order to achieve the United Nations Sustainable Development Goal (SDG) 6.1 ( https://unstats.un.org/sdgs/report/2021/goal-06/ ).…”

“…Bain et al. ( 2021 ) have explored this issue in their analysis, identifying a link between season and PoU water quality, but in-country comparisons better illustrate the impact. In Bangladesh, despite progress across all areas of water access, sanitation, and hygiene, the measured water quality results did not show similar improvements, with very minor gains at the PoC and a large deterioration at the PoU ( Bangladesh Bureau of Statistics and UNICEF Bangladesh 2021 ).…”

Differences in laboratory versus field treatment performance of point-of-use drinking water treatment methods: research gaps and ways forward

“…When such factors are represented in the data, then POUWT techniques can be viewed within the larger "source to sip" framework of HWTS, which encompasses the water source (in terms of protection, accessibility and sustainability), POUWT approaches and safe water storage and consumption 6 . By doing so, sustainable and scalable interventions can be made to reduce exposure to faecal contamination via drinking water and realize health gains, of which there is an urgent need 83 .…”