America’s aging water infrastructure is proving no match for heavier rainstorms fueled by climate change. The problem is especially severe—and smelly—in older cities like New York, where wastewater and stormwater are combined into the same set of sewer pipes. If these combined sewers take on more water than a treatment plant can handle, they spit the excess sewage and stormwater directly into local waterways.

Last year was a particularly rainy year in New York City. That meant raw sewage pulsed into the rivers and bays surrounding city one out of every three days on average. The pollution endangers aquatic life and makes it tough for boaters to enjoy a nice day on the water.

Faced with flashier storms, engineers and urban planners are reinventing how they deal with stormwater runoff. Rather than funnel it into sewer pipes—vulnerable to leaks or overflows—they are increasingly using plants and soil (“green infrastructure”) to soak it up. Green infrastructure has long been used to absorb stormwater that trickles off parking lots or school campuses. But more recent projects show that green infrastructure has made it to the big leagues—protecting entire cities from floods and storm surges.

Rebuilding from Hurricane Harvey, Houston is turning to green infrastructure to improve resilience to future disasters. New York City’s Staten Island Bluebelt project uses natural systems to collect and filter stormwater from more than 10,000 acres of the city. Cities like Detroit and Philadelphia have build dozens of green infrastructure projects across their urban landscape. Projects like these not only reduce flooding, but also provide space for recreation and wildlife habitat—so it might be time to ditch the stormwater pipes.