The Detroit branch NAACP hosted an event Friday to raise awareness about Detroit’s aging water infrastructure, and to call on the federal government to update and repair it.

Detroit’s situation is part of a nationwide infrastructure crisis, but the need is critical in the Great Lakes region, advocates say, because more than 30 million people depend on the lakes for their drinking water.

According to Palencia Mobley, Chief Engineer for Detroit Water and Sewarage, Detroit has 2,700 miles of water distribution lines that need replacing, and 700 miles of water transmission lines that feed the suburbs. Those lines cost $1.2 million per mile to replace, and the sewer system needs to be re-lined.

At the same time, the city is working to end sewer overflows during wet weather events. Discharges from storm sewers during heavy rains release raw sewage into the environment, threatening wildlife habitat, the recreation industry, and drinking water supplies.

All that would cost billions of dollars, and Mobley says that’s unaffordable for Detroit ratepayers. She says it’s important to seek funding from the federal government.