There are many cheap and effective ways to provide safe water to the world’s poor regions. But projects often fail due to inadequate planning, maintenance or persuasive power.

For more than 2 billion people, safe drinking water isn’t a given.

Not for them a clean, reliable supply of treated water splurting out on-demand from a kitchen tap — instead, they face often long treks to wells, rivers, pools of rainwater or faucets that yield water laced with disease-transmitting feces and other contaminants.

More than 500,000 deaths a year from diarrhea are linked to this very basic lack, and public health officials, philanthropic groups and researchers have worked to move the needle on the problem for decades.

So enthusiasm soared in the early 2000s for a new and compellingly simple approach. Instead of waiting for governments to act, or for projects that progressed at a snail’s pace, what if villages and households were empowered to clean water themselves?

A slew of cheap and easy technologies were available for the job.

From Ghana to Afghanistan to Bangladesh, development workers leaped to action. They fitted hand pumps to boreholes in rural communities. They held workshops explaining how a few hours of sunlight could purify water held in plastic bottles.

Households received ceramic filters that fit on tables, or larger sand filters cemented outside their doors. Volunteers promoted water-boiling, handed out bottles of chlorine and educated people about threats lurking in even the clearest-looking untreated water.

“Household water treatment was seen as potentially this huge revolutionary new model,” says Joseph Brown, an engineer in public health at Georgia Tech who spent much of his early career designing portable filters. “You could just deliver these devices, and everybody would start using them.”

In a community in Indonesia, a group of people in a yard are gathered around two tables, where about four dozen clear, plastic bottles of water lay on their sides.
In some parts of the world, like this community in Indonesia, residents take advantage of the Sun to treat their water. In good weather, six hours of direct sunlight can kill most dangerous microbes in clear water. Image by Sodis Eawag / Wikimedia Commons

The bad news

Then, in 2009, came the bucket of cold water. A newly published review argued that there was little solid evidence that household water treatment in poor rural regions was working: Placebo-controlled trials in Ghana, Gambia, and Brazil found no effect on the incidence of diarrhea.

Brown recalls that he was giving a talk at the World Bank in Washington, DC, about the benefits of treating water at the household level when, even as he spoke, someone in the audience was circulating copies of the paper.

It was “really the first skeptical paper that had come out around household water treatment — specifically to say that this method for providing safe water is totally bonkers,” Brown says.

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More criticism followed. People targeted for interventions didn’t seem to value treatments and weren’t willing to pay for them. They used treatment tools incorrectly or inconsistently, and usage dropped sharply over time.

In a trial that taught members of poor communities in Dhaka, Bangladesh, about water safety and supplied 600 households with two free months’ worth of water-treatment products, the devices went largely unused.

On-site visits, when asked if they had treated their water in the last day, more than 70 percent said no. “Adoption among the global poor is very low,” wrote the study authors, “and little evidence exists on why.”

For public health workers and researchers, it was a huge conundrum.

They knew the technologies could make water safe — the methods worked well in laboratory settings — so what was stopping these simple solutions from taking hold in the real world, with the people who needed them most?

That puzzle has spurred a sea change in research around water development.

Where once investigators asked what tools were best to gift to communities, they now ask why those “gifts” may have no impact. Questions of engineering and chemistry have given way to quite different questions about policy, maintenance, and the realities of human behavior.

“There’s no technology that eliminates the need for implementing well,” says Millie Adam, director of international partnerships at the Canadian charity Centre for Affordable Water and Sanitation Technology (CAWST).

“There are many organizations that have tried to find the silver bullet that you can just drop in, do it, and then check that community off the list and walk away. I don’t think that a solution exists.”

From lab to field

In 2015, member states of the United Nations set a package of development goals including universal safe water by the end of the next decade, with the ideal being safe, piped water delivered to homes and communities. The world is nowhere near on track.

Most researchers, public health officials, and development workers agree that household water treatment options can be crucial as interim solutions in emergencies or where no other resources are available — but experts are still divided on the role household water treatment should play in filling the gaps long-term.