Water quality and household water treatment

Why does household water quality and household water treatment (HWT) matter?

More than 1 billion people report treating their water at home before drinking it, mainly by boiling, filtration, and chemical disinfection.  When combined with safe storage, such point of use water treatment provides a way for vulnerable householders to address the combined risks of unsafe source water and recontamination of water during collection, storage and use in the home.  In this respect, it provides a means for householders to take charge of their own water security as they continue to wait for improvements in water supply that address deficiencies in water quantity and access, parameters that, like quality, are critical to overall health and well-being.  While household water treatment has been shown to have the potential to significantly improve drinking water quality, issues with correct and consistent use, which are essential for the effectiveness of household water treatment still remain an issue in low and middle-income countries.

Our research focuses on identifying the extent and conditions in which it HWT can actually prevent disease.  This includes laboratory assessments of microbiological performance of filters and disinfection methods, field studies to assess the consistency and effectiveness of treatment practices, behaviour trials to pilot and evaluate adoption of interventions, and rigorous randomized controlled trials to assess health impact in low-income settings as well as in emergency settings and among HIV-positive populations.

Key research and contributions to this area:

The Aquatab trial (Sophie Boisson, PhD)

Studies from low-income settings have found that HWT options could reduce diarrhoeal illnesses by between 30%–40%. However, many of these studies have had several methodological shortcomings including reporting bias, short follow up periods, small sample sizes, and many were not blinded. To overcome these limitations, our group conducted a large, double-blind, randomised placebo-controlled trial in Orissa, India. The study showed that the longitudinal prevalence of diarrhoea among children and adults was not significantly different between intervention and control groups. Additionally, there was also no difference in weight for age z scores (a measurement of growth) between children in the two groups. However, it should be noted that compliance in the intervention group was low.

Self- reported vs. actual use study (Ghislaine Rosa, PhD)

hwt_prevalence_map_78 low&middle income countries_Ghislaine Rosa

While most of the research in HWT has focussed on evaluating the efficacy or effectiveness of new technologies or promoting the uptake of HWT among non-users, over 1 billion people in low- and middle-income settings report using HWT. However, very little is known about the manner in which these population practice HWT, especially regarding the level of compliance or its effectiveness—key factors for reducing exposure and achieving the health benefits associated with HWT. Our research group undertook case studies in urban and rural communities in India, Zambia and Peru to understand the manner in which HWT was performed among households self-reporting the practice of HWT. While results varied substantially between sites, these case studies showed that households tend to over-report HWT use, that compliance was sub-optimal among reported users and that self-reported use was a poor predictor of drinking water quality in the home.


Assessing HWTS in Households with Young Children of HIV-Positive Mothers (Rachel Peletz, PhD)

Young children born to HIV-positive mothers are at greater risk of mortality, morbidity, and malnutrition, which may be aggravated by enteric infection. Safe water is critical for HIV-positive mothers who choose to replacement feed in order to prevent transmission of the virus via breast milk. However, “safe water and sanitation” is the first condition for replacement feeding in the new World Health Organization (WHO) guidelines for infant feeding for HIV-positive women. The guidelines recommend that virtually all women breastfeed their children for up to 2 years while either the mother or child is on antiretrovirals as the risks of diarrheal disease and malnutrition outweigh the risks of HIV transmission in the majority of low-income settings. Our group conducted a 12-month randomized, controlled field trial in Zambia among 120 households with children <2 years (100 with HIV-positive mothers and 20 with HIV-negative mothers to reduce stigma of participation) to assess the impact of a water filter (and jerry cans for safe storage) on diarrhoea. The study concluded that the water filter and safe storage combination was used correctly and consistently, was effective in improving drinking water quality, and was protective against diarrhoea.  

Current research in this area:

Our group is currently working in several HWT-related studies. Here are some examples of the work our candidate PhD students and staff are undertaking around the world.

Using salivary antibodies as markers of recent acute cryptosporidiosis in children under 5 in Zambia

Michelo Simuyandi, PhD candidate

Michelo is currently assessing whether salivary antibodies could be used as markers of recent acute cryptosporidiosis, a major pathogen that causes diarrhoeal disease in children under 5 years of age in developing countries. This approach could be very useful in intervention studies and monitoring and evaluation efforts as it could lead to the use of more objective outcome measures and less reliance on self-reported indicators such as self-reported diarrhoea.

Looking into the quality of ‘improved’ water sources: Evidence from Cambodia

Ameer Shaheed, PhD candidate

Current WHO guidelines classify water sources as “improved” or “non-improved” based on the type of water source and use these as proxy for monitoring access to water quality. This is due to the logistical constraints of performing direct water quality testing at the regional or national-level. However, this approach is recognised to be sub-optimal. As part of his PhD, Ameer conducted a study in Cambodia to investigate the quality of on-plot piped water and rainwater, two types of “improved” water sources, at the point of access and consumption. He found that water quality often did not meet World Health Organization standards at the source level. Additionally, he found that there was significant contamination between the point-of-access and point-of-use. His findings highlight the need for improved measurements, including quality, in global measurements such as the MDGs, and the need for improvements in water supply services and their maintenance in peri-urban areas of low-income countries. His findings also 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.

Assessing the acceptability and usage of a novel water treatment technologies

This study compared a novel water treatment technology with a pre-existing one, both primarily intended for short-term, emergency water treatment. The study aimed to assess how effective the new product was compared to other similar household-level water treatment technologies and also understand what factors caused higher and lower usage among our study populations. The study was implemented in two real-world settings: urban Lusaka, Zambia, and peri-urban Sindh, Pakistan, across approximately 250 households each setting.


A cluster randomized control trial to assess if the large scale, free distribution of water filters lead to a reduction in the incidence of health worker–diagnosed diarrhoea in Rwanda


Our group has been working for the past couple of year in Rwanda undertaking an independent evaluation of a program delivering free water filters and improved cooking stoves in the western province of the country. Initial phases of the study involved the execution of a randomised control trial to assess uptake, consistent use, and the impact on environmental exposures including air and drinking water quality. We also used sensors to assess use of the intervention in a more objective manner. These sensors were attached to the filters and measure the actual volume of water that passes through the filter. We are now working to undertake a large-scale, cluster randomised trial to assess whether the program has an impact on health worker-diagnosed diarrhoea, a more objective outcome measure.

girl_backwashing filter_Rwanda_DelAgua

Publications related to household water treatment:

  1. Assessing the impact of household water treatment with NaDCC tablet: a randomized, controlled trial in Orissa, India. BOISSON, S;  Stevenson, M; Shapiro, L; Kuman, V; Singh, LP; Ward, D; CLASEN, T.; PLOS  Med, In Press;
  2. Effect of Household-Based Drinking Water Chlorination on Diarrhoea among Children under Five in Orissa, India: A Double-Blind Randomised Placebo-Controlled Trial. BOISSON, S. ; Stevenson, M. ; Shapiro, L.; Kumar, V. ; Singh, L.P. ; Ward, D. ; CLASEN, T. ; PLoS Med, 2013; 10(8):e1001497
  3. The Impact of a School-Based Hygiene, Water Quality and Sanitation Intervention on Soil-Transmitted Helminth Reinfection: A Cluster-Randomized Trial.Freeman, M.C. ; CLASEN, T. ; BROOKER, S.J. ; Akoko, D.O. ; Rheingans, R. ; Am J Trop Med Hyg, 2013;
  4. Effective Use of Household Water Treatment and Safe Storage in Response to the 2010 Haiti Earthquake. Lantagne, D. ; CLASEN, T. ; Am J Trop Med Hyg, 2013;
  5. Preventing cryptosporidiosis: the need for safe drinking water. PELETZ, R. ; Mahin, T. ; Elliott, M. ; Montgomery, M. ; CLASEN, T.Bull World Health Organ, 2013; 91(4):238
  6. Follow-Up Study to Assess the Use and Performance of Household Filters in Zambia. PELETZ, R. ; SIMUYANDI, M. ; Simunyama, M. ; Sarenje, K. ; Kelly, P. ; CLASEN, T. ; Am J Trop Med Hyg, 2013;
  7. High adherence is necessary to realize health gains from water quality interventions. BROWN, J. ; CLASEN, T. ; PLoS One,  2012; 7(5):e36735
  8. Linking Quantitative Microbial Risk Assessment and Epidemiological Data: Informing Safe Drinking Water Trials in Developing Countries. Enger, K.S.; Nelson, K.L.; CLASEN, T.; Rose, J.B.; Eisenberg, J.N.S. Environmental  Science & Technology, 2012; 46(9):5160-5167
  9. Drinking Water Quality, Feeding Practices, and Diarrhea among Children under 2 Years of HIV-Positive Mothers in Peri-Urban Zambia. PELETZ, R. ; SIMUYANDI, M. ; Sarenje, K. ; BAISLEY, K. ; Kelly, P. ;  FILTEAU, S. ; CLASEN, T. ; Am J Trop Med Hyg, 2011; 85(2):318-26
  10. Assessing the Microbiological Performance and Potential Cost of Boiling Drinking Water in Urban Zambia. Psutka, R. ; PELETZ, R. ; Michelo, S. ; Kelly, P. ; CLASEN, T. ; Environ Sci Technol, 2011;
  11. Household Water Treatment and the Millennium Development Goals: Keeping the Focus on Health. CLASEN, T.F.; Environ Sci Technol, 2010; 44(19):7357-60
  12. Quantifying Health Improvements from Water Quantity Enhancement: An Engineering Perspective Applied to Rainwater Harvesting in West Africa. Fry, L.M.; Cowden, J.R.; Watkins, D.W.; CLASEN, T.; Mihelcic, J.R.;  Environ Sci Technol, 2010;
  13. Estimating the scope of household water treatment in low- and medium-income countries. ROSA, G.; CLASEN, T.; Am J Trop Med Hyg,  2010; 82(2):289-300
  14. Interventions to improve water quality and supply, sanitation and hygiene practices, and their effects on the nutritional status of children. DANGOUR, A.D. ; Watson, L. ; CUMMING, O. ; BOISSON, S. ; Che, Y. ; Velleman, Y. ; Cavill, S. ; ALLEN, E. ; UAUY, R. ; Cochrane Database Syst Rev, 2013; 8:CD009382
  15. Water, sanitation, and hygiene in emergencies: summary review and recommendations for further research. BROWN, J.; Cavill, S.; CUMMING, O.; JEANDRON, A. Waterlines, 2012; 31(1):11-29
  16. Hygiene, Sanitation, and Water: What Needs to Be Done? CAIRNCROSS, S.; Bartram, J.; CUMMING, O.; Brocklehurst, C.; PLoS Med, 2010; 7(11):e1000365
  17. Assessing the impact of a school-based water treatment, hygiene and sanitation programme on pupil absence in Nyanza Province, Kenya: a cluster-randomized trial. FREEMAN, M.C. ; Greene, L.E. ; Dreibelbis, R. ; Saboori, S. ; Muga, R. ; Brumback, B. ; Rheingans, R. ; Trop Med Int Health, 2011;
  18. Increasing equity of access to point-of-use water treatment products through social marketing and entrepreneurship: a case study in western Kenya. FREEMAN, M.C.; Quick, R.E.; Abbott, D.P.; Ogutu, P.; Rheingans, R.; J Water Health, 2009; 7(3):527-34
  19. The impact of a school-based safe water and hygiene programme on Knowledge and practices of students and their parents: Nyanza Province, western Kenya, 2006. O’Reilly, C.E.; FREEMAN, M.C.; Ravani, M.;  Migele, J.; Mwaki, A.; Ayalo, M.; Ombeki, S.; Hoekstra, R.M.; Quick, R.; Epidemiol Infect, 2008; 136(1):80-91
  20. Water quality perceptions and willingness to pay for clean water in peri-urban Cambodian communities. Orgill, J.; SHAHEED, A.; BROWN, J.; Jeuland, M. Journal of Water and Health, 2013; 11(3):489-506
  21. Water quality risks of ‘improved’ water sources: evidence from Cambodia. SHAHEED, A. ; Orgill, J. ; Ratana, C. ; Montgomery, M.A. ; Jeuland, M.A. ; Brown, J. ; Trop Med Int Health, 2013;
  22. Boiling as Household Water Treatment in Cambodia: A Longitudinal  Study of Boiling Practice and Microbiological Effectiveness. BROWN, J. ; Sobsey, M.D. ;Am J Trop Med Hyg, 2012;
  23. Microbiological effectiveness of locally produced ceramic filters for drinking water treatment in Cambodia. BROWN, J.; Sobsey, M.D.; J Water Health, 2010; 8(1):1-10
  24. Elise Presser, Michelo Simuyandi, Joe Brown. 2014. The Effects of Storage Time and Temperature on Recovery of Salivary Secretory Immunoglobulin A
  25. J Louis-Auguste, S Greenwald, M Simuyandi, R Soko, R Banda, P Kelly , 2014. High dose multiple micronutrient supplementation improves villous morphology in environmental enteropathy without HIV enteropathy: results from a double-blind randomised placebo controlled trial in Zambian adults.BMC gastroenterology 14 (1), 15
  26. Lantagne D, and Clasen T (2009). Point-of-use Water Treatment in Emergency Response. London School of Hygiene and Tropical Medicine, London, UK.
  27. Boisson S, Schmidt WP, Berhanu T, Gezahegn H, Clasen T. (2009) Randomized controlled trial in rural Ethiopia to assess a portable water treatment device. Environ Sci Technol. Aug 1;43(15):5934-9.
  28. Tiwari SS, Schmidt WP, Darby J, Kariuki ZG, Jenkins MW. (2009) Intermittent slow sand filtration for preventing diarrhoea among children in Kenyan households using unimproved water sources: randomized controlled trial. Trop Med Int Health. 14(11):1374-82.
  29. Boisson S, Tadesse G, Gezahegn H, Gerhanu T, Schmidt W-P, Clasen T (2009). A randomized controlled trial in rural Ethiopia to assess the LifeStraw personal water filter. Environmental Sci. & Tech. 43(15):5934–39
  30. Clasen T, Bartram J, Colford J, Luby S, Quick R, Sobsey M (2009). Comment on “Household Water Treatment in Poor Populations: Is There Enough Evidence for Scaling up Now?” Environmental Sci. & Tech. 43 (14), 5542-5544
  31. Clasen T, Naranjo J, Frauchiger D, Gerba C (2009). Laboratory assessment of a gravity-fed ultrafiltraton water treatment device designed for household use in low-income settings. Am J. Trop. Med. Hyg. 80(5) 819-823.
  32. Schmidt WP, Cairncross S. (2009) Household water treatment in poor populations: is there enough evidence for scaling up now? Environ Sci Technol. 15;43(4):986-92.
  33. *Clasen T (2009). Scaling Up Household Water Treatment and Safe Storage: in Low-Income Populations. Geneva: World Health Organization
  34. Brown, J. And Sobsey, M. 2009. Metal oxide amended ceramic media for the capture of viruses in drinking water. Environmental Technology 30(4): 379-391.
  35. Brown, J., Proum, S., and Sobsey, M. 2009. Sustained use of a household-scale water filtration device in rural Cambodia. Journal of Water and Health 7(3): 404-411.
  36. Lantagne D, Meierhofer R, Allgood G, McGuigan KG, and Quick R (2009). Comment on Point of use household drinking water filtration: a practical, effective solution for providing sustained access to safe drinking water in the developing world. Environ Sci Technol 43(3), 968-9; author reply 970-1.
  37. Kotlarz N, Lantagne D, Preston K, and Jellison K (2009). Turbidity and chlorine demand reduction using locally available physical water clarification mechanisms before household chlorination in developing countries. J Water Health7(3), 497-506.
  38. Boisson S, Kiyombo M, Sthreshley L, Tumba S, Makambo J, Clasen T (2010). Field assessment of a novel household-based water filtration device: a randomised, placebo-controlled trial in the Democratic Republic of Congo. PLOS One 5(9): e12613. doi:10.1371/journal.pone.0012613
  39. *Rosa G, Miller L, Clasen T (2010). The microbiological effectiveness of disinfecting water by boiling in Guatemala. Am. J. Trop. Med. Hyg. 82(3): 473-77
  40. *Clasen T (2010). Household water treatment and safe storage in low-income countries, in Selendy J., et al. (eds.) Water and Sanitation Related Diseases and the Environment: Challenges, Interventions and Preventive Measures. New York: Wiley and Sons.
  41. Lantagne D (2010). Comment on An observational study on the effectiveness of point-of-use chlorination. J Environ Health 72(2), 38-9.
  42. Lantagne D, Klarman M, Mayer A, Preston K, Napotnik J, and Jellison K (2010). Effect of production variables on microbiological removal in locally-produced ceramic filters for household water treatment. Int J Environ Health Res 20(3), 171-87.
  43. Lantagne D, Preston K, Blanton E, Kotlarz N, Gezagehn H, van Dusen E, Berens J, and Jellison K (2011). Hypochlorite solution expiry and stability in household water treatment in developing countries. Journal of Environmental Engineering 137(2), 131-6.
  44. *Freeman M., Clasen T (2011). As assessment of the impact of a school-based safe water intervention on household adoption of point-of-use water treatment practices in Southern India. Am. J. Trop. Med. Hyg. 84(3):370–378
  45. *Peletz R, Simuyandi M, Sarenje K, Baisley K, Kelly P, Filteau S, Clasen T. (2011) Drinking Water Quality, Feeding Practices and Diarrhea Among Children Under 2 Years of HIV-Positive Mothers in Peri-Urban Zambia. Am. J. Trop. Med. Hyg. 85(2).
  46. Sodium dichloroisocyanurate (NaDCC) tablets as an alternative to sodium hypochlorite for the routine treatment of drinking water at the household level. CLASEN T, Edmondson P (2006) Int’l J. Hyg. & Environ. Health [epub ahead of press: doi:10.1016/j.ijheh.2005.11.004]
  47. Interventions to improve water quality for preventing diarrhoea (Cochrane Review). CLASEN T, Roberts I, Rabie T, Schmidt W-P, Cairncross S (2006) In: The Cochrane Library, Issue 3, 2006. Oxford: Update Software (in press)
  48. Microbiological performance of a water treatment unit designed for household use in developing countries. CLASEN T, Nadakatti S, Menom S (2006) Trop. Med. Int’l Health (in press)
  49. Preventing diarrhoea with household ceramic water filters: assessment of a pilot project in Bolivia. CLASEN T, Brown J, Collin S (2006) Intl J. Environ Health Research (in press)
  50. The Drinking Water Response to the Indian Ocean Tsunami, including the role of household water treatment. CLASEN T and Smith L. Protection of the Human Environment: Water, Sanitation and Health, Geneva 2005.
  51. Household-based ceramic water filters for the prevention of diarrhea: a randomized, controlled trial of a pilot programme in Colombia CLASEN T, Parra GG, Boisson S, Collin S. American Journal of Tropical Medicine and Hygiene. 2005 Oct; 73(4):790-5.
  52. Clasen TF, Cairncross, S. 2004. Editorial: Household water management; refining the dominant paradigm. Tropical Medicine and International Health 9 (2): 187-191.
  53. Safe household water treatment and storage using ceramic drip filters: a randomised controlled trial in Bolivia. CLASEN T, Brown J, Suntura O, Collin S. Water Science and Technology. 2004; 50(1):111-5.
  54. Household water management: refining the dominant paradigm. CLASEN T, CAIRNCROSS S. Tropical Medicine and International Health. 2004 Feb; 9(2):187-91.
  55. Reducing diarrhea through the use of household-based ceramic water filters: a randomized, controlled trial in rural Bolivia. CLASEN T, Brown J, Collin S, Suntura O, CAIRNCROSS S. American Journal of Tropical Medicine and Hygiene. 2004 Jun; 70(6):651-7.
  56. Is there an association between bacteriological drinking water quality and childhood diarrhoea in developing countries? Jensen PK, Jayasinghe G, van der Hoek W, CAIRNCROSS S, Dalsgaard A. Tropical Medicine and International Health. 2004 Nov; 9(11):1210-5.
  57. Effect of chlorination of drinking-water on water quality and childhood diarrhoea in a village in Pakistan. Jensen PK, Ensink JH, Jayasinghe G, van der Hoek W, CAIRNCROSS S, Dalsgaard A. Journal of Health and Population Nutrition. 2003 Mar; 21(1):26-31.
  58. Faecal contamination of drinking water during collection and household storage: the need to extend protection to the point of use. CLASEN TF, Bastable A. Journal of Water and Health. 2003 Sep; 1(3):109-15.
  59. Domestic transmission routes of pathogens: the problem of in-house contamination of drinking water during storage in developing countries. Jensen PK, ENSINK JH, Jayasinghe G, van der Hoek W, CAIRNCROSS S, Dalsgaard A. Tropical Medicine and International Health. 2002 Jul; 7(7):604-9.
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