Across about 25% of Pittsburgh, sewage and stormwater are routed into separate underground sewer pipes. When it rains, stormwater enters inlets and storm sewer pipes send it directly to our streams and rivers, along with any harmful pollutants picked up on the ground surface or in the below-ground network.

The City of Pittsburgh and PWSA operate under a Municipal Separate Storm Sewer System (MS4) permit from the Pennsylvania Department of Environmental Protection (DEP). This permit requires that we follow specific regulations and implement practices to reduce pollutants from our storm sewer system. It also means implementing a plan to ultimately reduce discharge of pollutants into waterways. This is managed under six Minimum Control Measures focused on public education and outreach, illicit discharge detection and elimination, pollution prevention and good housekeeping practices in our operations, and more.

Meeting these water quality goals will mean working collaboratively with other local stakeholders to develop stormwater management plans for Pittsburgh’s unique geography and existing infrastructure. This includes mapping the entire separate sewer system, establishing an inventory of potential and known sources of pollution, and investigating and inspecting all outfalls routinely or in response to reported illicit discharges or suspected pollution concerns.

To learn more about PWSA’s MS4 Permit, visit www.pgh2o.com/MS4.