SHRI's India toilet blocks sell cleaned groundwater to pay for their own upkeep

India has 600 million people without access to a clean toilet, and Prime Minister Narendra Modi's Clean India campaign aims to provide decent sanitation to all by 2019. But critics say the program under-weighs human factors and that the money on offer has bred corruption — toilets get built, then decay.

SHRI, formerly called Humanure, designed around the decay problem. It builds 16-toilet community blocks — eight for women, eight for men — sized for villages of 1,500 people, over a large collection tank. Waste degrades and gives off biogas, which runs an electric generator; the electricity cleans groundwater, which SHRI sells to offset the cost of keeping the toilets clean.

The economics show up in usage: the blocks are free to use, and DeGennaro says they average 800 users a day. By 2016 SHRI had built four blocks in Bihar state, joined Y Combinator's nonprofit batch with a $100,000 grant, and was fundraising in Silicon Valley on the strength of that revenue-generating element.

Building toilets is the easy half; upkeep is where most sanitation projects die, so SHRI wired maintenance into the revenue model.

Selling water monetizes a byproduct villagers already need, without charging the people the toilets are for.

Free access keeps usage high — which keeps the biogas flowing — unlike fee-charging projects that price out users.

A service fails when its maintenance has no budget: give the facility a product to sell and the byproduct pays for the upkeep forever.

Four blocks were operating in Bihar, each averaging 800 users a day. SHRI joined Y Combinator's 2016 nonprofit batch, took a $100,000 grant, and was pushing to tap both Indian government toilet funds and Silicon Valley investors, with co-director Joan DeGennaro pitching the water revenue as the sustainable element.