When Detroit began shutting off the water supply to thousands of the city’s poorest and most vulnerable residents who were behind on their water bills in 2014, U.N. experts called it a violation of human rights . Three years later, the same thing is still happening. On April 19, Detroit Water and Sewerage Department began another round of mass shutoffs.

One nonprofit has a simple way to help: If you donate money, they’ll use it to pay off overdue bills.

The Human Utility first launched in 2014 as the Detroit Water Project, when cofounder Tiffani Bell–a Code for America fellow at the time, based in Oakland–read about the situation in Detroit and started tweeting about it. As she dug around on the water company’s website, she found a list of delinquent accounts and began to speculate about helping pay them off. Bell worked remotely with another volunteer she met on Twitter (Kristy Tillman, now head of communication design at Slack) to quickly build a website to connect donors with people in need.

Initially, volunteers manually matched donors with people who reached out for help. Now, all donations go into one pool, and anyone with an overdue bill fills out an application that automatically screens them for qualification; they also provide supporting documents like pay stubs.

Since launching, the tiny nonprofit has helped nearly 1,000 families. “There’s some people who were living without water for a while,” Bell tells Fast Company. “There’s a lady who wrote an email that hangs over my door who talks about how she and her son were very sick, and they had to live without running water in their house for six months until we helped them. They were doing things like trying to drink from their neighbor’s water hose. Now they don’t have to.”

After going through the Y Combinator program in early 2015, the organization expanded to also work in and around Baltimore, where the donations have helped some families keep their homes.

“You can lose your house over a water bill as well,” she says. “If you don’t pay it…they’ll essentially tack the bill onto your property taxes. So if you don’t pay the property taxes, you’ll lose the house in a tax sale.” Since 2015, the organization has helped around 40 families in Baltimore stay in their houses.