narrator: in the pittsburgh system, 83 cities and towns use the same sewage treatment plant -- alcosan. so all 83 municipalities have to work together to address the problem. schombert: we know we have billions of dollars that will have to be spent over the next 15 to 20 years. you can't do that wisely when you have 83 separate government agencies making decisions. the municipal consent orders and the alcosan consent decree require that the municipalities participate in a long-term, regional wet weather control plan. narrator: the information gathered in the initial research phase of the wet weather control plan will inform the large-scale infrastructure overhaul. and, as this research moves forward, pittsburgh is also working with environmental groups that are cleaning up the watershed. woman: make that connection. man: like a mural on the side of a building? woman: $5.00 to get in. man: there's water flowing under the ground right now. i really think a lot of people don't know that. that's a critical area, because everything that's dropped on the ground is part of your watershed now.