Recontamination of Water is a Widespread Problem

Access to a safe water source is an important first step, but it does not guarantee that the water a family drinks will remain safe. Water can become contaminated during collection, transport, storage, and handling between the source and the drinking cup.

The World Health Organization (WHO) and UNICEF recognize this as an important water-quality challenge. Their guidance emphasizes that household water treatment and safe storage can help prevent contamination during collection, transport, and use in the home.¹ UNICEF similarly states that even water that is safe at its source can become contaminated unless it is treated, transported, stored and handled safely.²

Recent analysis from the World Bank demonstrates how widespread the problem is. In 28 of 30 countries with comparable data, contamination was more common when water was tested inside the household than when it was tested at the original source.³ The World Bank describes this as a gap between water that is safe at the source and water that is safe by the time it reaches the glass.

Research also shows that contamination can occur surprisingly quickly. In a study in Eastern Uganda, researchers found that 86% of initially clean water samples contained E. coli after 24 hours of storage in jerrycans.⁴ The study found that cleaning containers and using storage vessels designed to reduce contact with hands and other contamination sources could substantially reduce recontamination.

Research associated with Harvard University has reached a similar conclusion. A randomized study of protected springs in Kenya found that protecting the water source reduced fecal contamination at the source by approximately two-thirds, but the improvement in water quality at the household was much smaller. Researchers concluded that recontamination during transport and storage was likely a major reason for the difference.⁵

This is why safe drinking water requires more than a safe source. The entire pathway matters:

Safe Source → Safe Collection → Safe Transport → Safe Storage → Safe Handling → Safe Drinking Water

For communities where families collect water away from home, a complete water solution should therefore address not only the quality of the source, but also what happens to the water afterward. Household filtration, clean containers, covered storage, hand hygiene, and safe dispensing can provide additional barriers against contamination.

CAWST, a Canadian organization specializing in household water treatment and safe storage, describes this as a “multi-barrier approach” that addresses risks at the source, during transportation, and during storage.⁶

At Mighty Water, this principle is central to our approach. Providing a filter is only part of the solution. Families also need practical training in filtration, cleaning, storage, hygiene, and safe handling so that clean water remains clean until it is consumed.

Clean water is not simply about where water comes from. It is about protecting water all the way to the glass.

1. 2012, World Health Organization, Considerations for policy development and scaling-up household water treatment and safe storage with communicable disease prevention efforts, https://www.who.int/publications/m/item/considerations-for-policy-development-and-scaling-up-household-water-treatment-and-safe-storage-with-communicable-disease-prevention-efforts
2. 2026, UNICEF, Water, https://www.unicef.org/wash/water
3. 2026, World Bank, Water quality: safe at the source isn't safe at the glass, https://blogs.worldbank.org/en/opendata/water-quality--safe-at-the-source-isn-t-safe-at-the-glass
4. 2021, Water Research X, Keeping water from kiosks clean: Strategies for reducing recontamination during transport and storage in Eastern Uganda, https://www.sciencedirect.com/science/article/pii/S2589914720300396 
5. 2010, Harvard Environmental Economics Program, Spring Cleaning: Rural Water Impacts, Valuation, and Property Rights Institutions, https://heep.hks.harvard.edu/publications/spring-cleaning-rural-water-impacts-valuation-and-property-rights-institutions
6. 2017, CAWST, The Multi-Barrier Approach to Safe Drinking Water, https://washresources.cawst.org/en/resources/65154a07/the-multi-barrier-approach-to-safe-drinking-water