Population Services International (PSI)
WaterGuard is a dilute sodium hypochlorite solution used as a point-of-use treatment for household drinking water.
WaterGuard (also know as Sur’Eau in French-speaking regions) is a household chemical water treatment method distributed by Population Services International (PSI). This point-use water treatment is a controlled chlorine dosing method. It does not require the level of monitoring or use of complex equipment like traditional gas systems. WaterGuard is part of the Safe Water System (SWS), a water quality intervention program to be used in collaboration with safe water storage, and behavioral change communication. Correct use of the product in combination with SWS has shown to reduce diarrheal disease incidence in users by 22-85%.
The PSI is the major community distributor. Partnerships with PATH (funded by the Bill and Melinda Gates Foundation & CDC), the University of Malawi in conjunction with CDC, Pan American Health Organization (PAHO) and World Health Organization (WHO), have also facilitated distribution and implementation of the product.
SDG 6: Clean water and sanitation
Individuals or households using contaminated water sources.
The product is listed as locally manufactured, details on the manufacturing process are not discussed.
The product is open-sourced. The recommended concentration level is registered under a number of American agencies, including US-EPA, NSF/ANSI60, State registrations, and the US Department of Agriculture.
Users are most likely to purchase WaterGuard from their local supermarket, pharmacy, or street vendors. In some rural areas, users can contact WaterGuard’s community sales agents to obtain the product.
Active chemical and concentration (%) of the product (not the concentration of the treated water)
Form of the chemical disinfection
Does the water flow through a treatment system or does it remain in a container?
Is the dose of the chemical administered automatically or manually?
Manufacturer-specified dosing quantity
Manufacturer-specified time until water is potable, measured in minutes
Remaining level of chemical concentration after manufacturer-specified contact time
Laboratory-evaluated log scale removal rate of bacteria
Laboratory-evaluated log scale removal rate of viruses
Laboratory-evaluated log scale removal rate of protozoa
Reduction levels of heavy metals and/or arsenic through this treatment system
How long can the treated water remain protected and safe to drink?
Manufacturer-specified maximum level of inlet turbidity (NTU)
The water treatment product is made from sodium hypochlorite, 12.5% diluted to 1.25% by weight.
The 150mL standard bottle is suggested to serve a family’s water needs for approximately a week. The cap is used for measuring doses, with one cap referred to as a single dose. A cap of WaterGuard 3mL is added to 20L of water >30NTU, in a container with a tight-fitting lid. The container is agitated and left for 30min for sanitation to complete. Two caps are required for water with high turbidity levels (>100NTU), with pre-filtration methods recommended before the addition of WaterGuard.
WaterGuard is packaged in a 150mL bottle with a 3mL cap.
Sodium hypochlorite degrades over time. Studies have found that in ideal conditions, chlorine concentration significantly decreases. Products of original concentration 13% sealed, at 80F, away from direct sunlight, were found to decrease in concentration to 8% over 75 days. This should be taken into account when treating water.
Users must consult Federal, State, and Local regulations for disposal.
This water treatment is designed to remove 99.9% of bacteria.
The product should be used as per dosage guidelines. The maximum use limit must not exceed 84mg/L. This product should not be mixed directly with any other chemical.
Microbiological effectiveness is limited by turbidity of the raw water. The effectiveness of WaterGuard decreases proportionately to turbidity levels. WaterGuard is unable to effectively treat raw water with turbidity levels greater than 100NTU.
The use of chlorine water treatment is hazardous if incorrectly monitored. Trihalomethanes (THMs) are formed in drinking-water as a result of chlorination of organic matter present in raw water supplies. High concentrations of these compounds are linked to a variety of health issues such as cancer and reproductive issues. The World Health Organisation advises THM levels in drinking water to be kept as low as possible. The point-of-use chlorination of water in Kenya has shown compliance with WHO THM guideline values.
If the water turbidity is greater than 30NTU, 2 caps must be used. Preliminary filtration using a cloth is recommended before adding WaterGuard.
If NTU is greater than 100NTU alternative treatments should be used, as WaterGuard is ineffective at these levels.
Luoto, et al. 2011, What point-of-use water treatment products do consumers use? Evidence from a randomized controlled trial among the urban poor in Bangladesh, PLoS One; 6(10): e26132
Reller et al., 2001, Cholera Prevention With Traditional and Novel Water Treatment Methods: An Outbreak Investigation in Fort-Dauphin, Madagascar, Vol91, No.10
Tersagh, I, et al., 2015. Efficacy of Water Guard Disinfectant as a Domestic Stored Water Treatment Method in Makurdi Metropolis. Research Journal of Environmental Sciences, 9: 364-369.
Mohamed, H., et al, 2015, Point-of-use chlorination of turbid water: results from a field study in Tanzania, Journal of Water and Health, 13 (2): 544-552.
Yohanna, L., and Mashauri, D., 2008, Potential Use of WaterGuard as a disinfectant for domestic water use Tanzania Journal of Engineering and Technology 31(2): 62-69
Lule JR., et al. 2005, Effect of home-based water chlorination and safe storage on diarrhea among persons with human immunodeficiency virus in Uganda. American Journal of Tropical Medicine & Hygiene. 2005;73(5):926‐933.
The product is endorsed by PSI and complies with the South African National Standard 241 Drinking Water Specifications.
The manufacturer product cites log 4 removals of bacteria for water treated with WaterGuard. The evaluation criteria primarily are for the removal of E.coli, E. Histolytica, G. Lambilia, Cryptosporidium enteroviruses. Third-party testing is conducted by the CDC.
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