Nothing builds camaraderie like joining forces in a sticky situation.

For the 83 municipalities served by Allegheny County Sanitary Authority, ALCOSAN, a persistent problem is when sewage overwhelms combined storm and sewer systems and spills untreated into the rivers.

As part of the effort to reduce combined sewer overflows, ALCOSAN intends to take over maintenance and management of about 200 miles of shared sewer pipes in the region.

ALCOSAN’s plant sits under the McKees Rocks Bridge on Pittsburgh’s North Side. Imagine sewage conveyance to the plant as a sort of mechanical handoff: depending on proximity, sewer pipes coming from one municipality may flow into pipes owned by another municipality before reaching ALCOSAN’s large pipes, called trunk lines.

For instance, 24 municipalities discharge their sewage directly into Pittsburgh Water and Sewer Authority’s system, said Bob Weimar, PWSA’s executive director.

“They are some of the oldest [pipes] in our system,” he said. “From our point of view we’ve got a lot of work to do and if they’re willing to take those sewers that we have sort of the least direct benefit from, maybe that would be a good idea.”

ALCOSAN, as well as the region’s municipalities, must reduce combined sewer overflows in order to meet state and federal environmental regulations. The shared sewer infrastructure transfer is expected to be part of an updated consent decree ALCOSAN is negotiating with the federal government.

The move is expected to keep costs down for ratepayers, said Joey Vallarian, ALCOSAN’s director of communications. The authority can marshall more resources to repair or maintain these sewers than muncipalities.

The details of the transfers are yet to be finalized.

“We’re working with all of our municipalities including PWSA to further the project,” said Vallarian.