Understanding preferences for point-of-use chlorination in peri-urban communities in Cambodia

Economic cost-benefit analyses suggest that point-of-use (POU) treatment of drinking water can provide large health and welfare gains to households in developing countries. At the same time, penetration and sustained use of these technologies often remains modest. We hypothesized that the low demand for these and other health-improving technologies may be related to disamenities that are difficult to measure, or may be associated with the perceived or real costs of behavior change. This study aimed to measure the economic implications of such disamenities. Working in two communes in a region where there is known resistance to chlorinated water, we implemented a set of preference experiments alongside community water quality and health assessments. These experiments included blinded taste tests of disinfection products and discrete choice experiments to elicit preferences for different attributes of water treatment. We then extended this work to study whether and how provision of household-specific information on water quality affects the demand for water treatment, by considering heterogeneity in household responses to information.

cambodia water treatment - typical rainwater collection system in Kandal Province

Typical rainwater collection system in Kandal Province.

Main research collaborators:

  • Jennifer Orgill; Gina Turrini; Amar Hamoudi (Duke)
  • Joe Brown (Georgia Technological University)
  • Ameer Shaheed (London School of Hygiene and Tropical Medicine)
  • Geoff Revell, Ratana Chai (WaterSHED-Cambodia)

Survey Instruments:

Baseline survey: July/August 2011

Round 2: June/July 2012

Round 3: July/August 2012 (5-6 weeks after round 2)

Related Publications:

Brown, J.; M. Jeuland; A. Hamoudi; G. Turrini (2015). “Seeing, believing, and behaving: Heterogeneous effects of an information intervention on household water treatment.” Revision requested.

Abstract: Previous research indicates that providing people with information about health risks does not always motivate them to take protective action, and when it does the effect is often modest. Those findings raise questions about whether and how information about health risks is understood and acted upon, including whether and how responses vary across contexts and over time. We stratified a randomized experiment across two periurban areas located near Phnom Penh, Cambodia, which were identified in preparatory work to be different in terms of socioeconomic status, piped water coverage, and perceptions of water safety. In each area, we compared effects of providing drinking water quality test results on subjective beliefs of water safety, demand for a chlorine-based water treatment product, and hygiene-related behaviors. In one area, showing households evidence that their water was contaminated increased the purchase and use of the treatment product and altered water safety beliefs over a 6-week period, while in the other it had no significant effect on beliefs and only affected self-reports of hand-washing. These differential effects suggest a need for better understanding the drivers of responses to health risk information interventions.

Jeuland, M.; J. Orgill, A. Shaheed, A., G. Revell & J. Brown (2012). “A matter of good taste: Investigating preferences for in-house water treatment.” Environment and Development Economics (Accepted).

Abstract: Low demand for safe water may partly result from perceived distaste or inconvenience of treatment methods. This paper analyzes preferences for water quality improvements in peri-urban Phnom Penh. We first analyze data from a discrete choice experiment in which respondents selected their preferred alternative from generic options varying in cost, taste acceptability, effectiveness against diarrhea, and quantity of water treated. The choice patterns in suggest that demand for water treatment is highly dependent on taste acceptability. We also use double-blinded taste tests to show that respondents are sensitive to one common taste in treated drinking water, that stemming from chlorine disinfection. While many compounds (natural and anthropogenic) may contribute to taste problems in drinking water, the lack of alignment between household preferences for taste and water safety may play a role in the low use of household water treatment methods in many settings.

Shaheed, A.; J. Orgill; M. Montgomery; M. Jeuland; J. Brown (2014). “Why “improved” water sources are not always safe.” Bulletin of the World Health Organization 92:283-289.

Abstract: Existing and proposed metrics for household drinking-water services are intended to measure the availability, safety and accessibility of water sources. However, these attributes can be highly variable over time and space and this variation complicates the task of creating and implementing simple and scalable metrics. In this paper, we highlight those factors – especially those that relate to so-called improved water sources – that contribute to variability in water safety but may not be generally recognized as important by non-experts. Problems in the provision of water in adequate quantities and of adequate quality – interrelated problems that are often influenced by human behaviour – may contribute to an increased risk of poor health. Such risk may be masked by global water metrics that indicate that we are on the way to meeting the world’s drinking-water needs. Given the complexity of the topic and current knowledge gaps, international metrics for access to drinking water should be interpreted with great caution. We need further targeted research on the health impacts associated with improvements in drinking-water supplies.

Shaheed, A.; J. Orgill; R. Chai; M. Montgomery; M. Jeuland; J. Brown (2014). “Water quality risks to “improved” water sources: evidence from Cambodia” Tropical Medicine and International Health 19(2): 186-194. doi: 10.1111/tmi.12229.

Abstract:

Objectives: The objective of this study was to investigate the quality of on-plot piped water and rainwater at the point of consumption in an area with rapidly expanding coverage of improved’ water sources.
Methods: Cross-sectional study of 914 peri-urban households in Kandal Province, Cambodia, between July–August 2011. We collected data from all households on water management, drinking water quality and factors potentially related to post-collection water contamination. Drinking water samples were taken directly from a subsample of household taps (n = 143), stored tap water (n = 124), other stored water (n = 92) and treated stored water (n = 79) for basic water quality analysis for Escherichia coli and other parameters.
Results: Household drinking water management was complex, with different sources used at any given time and across seasons. Rainwater was the most commonly used drinking water source. Households mixed different water sources in storage containers, including ‘improved’ with ‘unimproved’ sources. Piped water from taps deteriorated during storage (P < 0.0005), from 520 cfu/100 ml (coefficient of variation, CV: 5.7) E. coli to 1100 cfu/100 ml (CV: 3.4). Stored non-piped water (primarily rainwater) had a mean E. coli count of 1500 cfu/100 ml (CV: 4.1), not significantly different from stored piped water (P = 0.20). Microbial contamination of stored water was significantly associated with observed storage and handling practices, including dipping hands or receptacles in water (P < 0.005), and having an uncovered storage container (P = 0.052).
Conclusions: The microbial quality of ‘improved’ water sources in our study area was not maintained at the point of consumption, possibly due to a combination of mixing water sources at the household level, unsafe storage and handling practices, and inadequately treated piped-to-plot water. These results have implications for refining international targets for safe drinking water access as well as the assumptions underlying global burden of disease estimates, which posit that ‘improved’ sources pose minimal risks of diarrhoeal diseases.

Orgill, J.; M. Jeuland; A. Shaheed; J. Brown (2013). “Water quality perceptions and willingness to pay for clean water in peri-urban communities in Cambodia.” Journal of Water & Health 11(3): 489-506. doi:10.2166/wh.2013.212.

Abstract: This paper studies household demand for improved water quality in peri-urban Cambodia, with particular attention paid to the influence of water quality on willingness to pay (WTP). Utilizing data from 915 household surveys, we analyze responses to a contingent valuation scenario using multivariate logit regression techniques that account for subjective perceptions of water quality. We estimate a mean household WTP for improved water quality of US$3 (roughly 1.2% of mean income) per month for households in this sample. We also find that the majority of households believe that their in-house water after storage, handling, and treatment is safe to drink. Furthermore, beliefs about existing levels of water quality have a significant impact on WTP for improved water quality. However, while perceptions of quality (and thus WTP) are highly related to taste preferences, actual water quality is relatively uncorrelated with water quality perceptions. These findings suggest that interventions aiming to increase the adoption of water treatment should account for underlying perceptions of water quality.