Clogged Sewer Pipe May Have Worsened Bay View Flooding

Flooding on S. 2nd St. Photo by Jeramey Jannene.

A massive sewer pipe clogged with debris seems to have played a role in the local flooding that followed heavy rain this spring.

A Milwaukee Metropolitan Sewerage District (MMSD) sewer pipe used to divert stormwater into Lake Michigan was likely clogged with debris when heavy rain caused flash flooding in April. The pipe, which is located on Jones Island in the Port of Milwaukee, is one of two combined sewer overflow pipes that are opened up directly to the lake when MMSD’s Deep Tunnel storage facility is at capacity. The overflow pipes, a network of which also discharge to the city’s rivers, are only used during historically rare rain events. In less than a year, Milwaukee has had two such storms.

Kevin Shafer, MMSD executive director, declined to say Wednesday whether the clogged pipe directly caused or contributed to the significant flooding in the nearby Bay View neighborhood. Shafer did allow that “it didn’t help the matter.”

Following the floods in April, Ald. Marina Dimitrijevic pressed MMSD for answers about now persistent issue in her district. At the time, MMSD did not indicate it could be related to a clogged sewer overflow pipe.

The sewerage district first realized there was debris in the pipe in early 2025, Shafer said. At the time, MMSD was working with the Michels Corporation to move the mouth of the pipe to make way for a basin that will be filled with contaminated material dredged from the Menomonee, Kinnickinnic and Milwaukee rivers. But it wasn’t until June 26 of this year that MMSD officials realized the sewer pipe was actually plugged up with debris, Shafer said.

Between those two points in time, Milwaukee experienced two massive rainfalls, both of which produced flash flooding, particularly in Bay View. During the storm in August, the flooding was so widespread across the region that it did not lead MMSD officials to suspect debris in the overflow pipe was part of the problem.

“Even if the pipe had been open, I think you would have had backups in the area just because the size of the storm,” Shafer said.

In April, however, Shafer said there were unusual hydraulic conditions upstream in the system that led MMSD to reconsider the overflow pipe. In June, construction crews dug down to the pipe, cut the top off and found it was “totally blocked,” Shafer said.

Shafer said MMSD is waiting on the results of further hydraulic analysis and modeling before it can determine whether the flooding was directly caused by the flooded overflow pipe.

Dimitrijevic released a statement Wednesday saying she was “angry and deeply disappointed to have just learned that a blocked overflow… may have contributed to the extraordinary flooding experienced by Bay View residents and businesses.”

Dimitrijevic is calling for restitution payments to homeowners, renters and businesses that suffered damages due to the flooding caused by failures of public infrastructure. The alderwoman named The Mothership, 2301 S. Logan Ave., and Wrought Washer Manufacturing, 2100 S. Bay St., in particular, saying, “They pay for this service and it failed them miserably.”

Responding to a question about restitution Wednesday, Shafer said, “Right now we just want to try to fix it, and we’ll see what happens with [investigations]. So I don’t know the answer.”

MMSD has recently come under public scrutiny for allegations that its private wastewater operator, Veolia Water Milwaukee, is mismanaging operations at the Jones Island and South Shore water treatment facilities. Common Ground Southeastern Wisconsin is working with whistleblowers who allege Veolia is cutting corners to save money, leading to machine failures and causing the plants to run under capacity, increasing the risk of sewer overflows and basement backups.

The pipe in question is not Veolia’s responsibility to inspect and maintain, Shafer said. MMSD is clearing out the debris, which includes large tree branches and trash, and plans to install a flap-gate at the pipe opening in Lake Michigan. The opening does not currently have any covering, and Shafer speculated that some of the large debris may have washed into the pipe from the lake.

“As the lake levels have gone up and down, it may have been at those lower levels,” he said. 

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