It is an idea so simple it can’t fail. To improve sanitation in developing countries, an American firm has designed a toilet that retails for $1.85.

In 2011 the Gates Foundation launched a high-profile campaign among academics to reinvent the toilet. Inspired by the challenge, American Standard, a plumbing company, dispatched a team to Bangladesh to see if there was a market for a cheap, sanitary toilet. Existing facilities were wholly inadequate—large vats in the ground covered by a concrete slab with a hole in the top. When the vat was full, it is emptied by sweepers, a deeply unpleasant and dangerous task. It is the absence of a seal on these toilets that contributes many of the problems surrounding sanitation. There is no block on smell, nothing to stop flies spreading bacteria from the waste, and no incentive for users to keep them clean.

Since developing the sanitary toilet (dubbed SaTo) in 2012, the company has sold 100,000 units across Bangladesh. Design constraints were considerable: it had to be manufactured to a competitive price, use minimal water, and require no change in behavior. The SaTo is a bright blue piece of tough moulded plastic that looks rather like the business end of a trombone. It uses half a liter of water to form a seal against smells and bugs. It is manufactured and distributed by a local firm, using recycled material, mostly old chairs. Low input and labor costs, combined with the fact that it is retrofitted to existing facilities, has kept the price affordable for most.

American Standard The SaTo

The World Health Organisation estimates that inadequate sanitation costs the global economy $260 billion a year. Open toilets and latrines lead to bacteria being ingested and a range of intestinal diseases. Workers spend valuable time traveling to distant, communal toilets on journeys that are often unsafe, especially for young women. Defecating in the open—still practiced widely in South Asia—ensures the contamination of agriculture and waterways. The human cost is higher still: two million people die every year from diarrhea; the WHO has discovered that improving sanitation is the most effective way of reducing this number.

American Standard’s vice-president of research, Jim McHale told Quartz, “Setting up a business model whereby people can buy an affordable, aspirational, locally manufactured product allows us to reach far more people than with a purely philanthropic approach.”

The success of the SaTo in Bangladesh has led McHale to try and apply the same principles elsewhere. Research is ongoing in Zambia, where water scarcity means the volume of water required will have to be reduced further. The absence of concrete floors—latrines are often covered with mud and wood—means the shape will have to be rethought. But American Standard’s big target is India, where 620 million people live without clean toilets.

The timing might be right: newly elected prime minister, Narendra Modi, famously tried to offset concerns about his Hindu-nationalist links by promising to build “toilets, not temples” during his election campaign, and in his first Independence Day speech he gave his government a year to install separate girls and boys toilets in every school in the country.

“The benefits that toilets provide around comfort, convenience, security, and dignity could be more attractive selling points than health and hygiene,” says McHale. “If we get more people using good, hygienic toilets the public health benefits will be there, but by focusing on selling the other, more aesthetic benefits, we will realize them faster.”