For weeks some Ironton residents have sworn there had to have been a blockage in the city’s sewer system that was causing sewer backup into their basements and bathrooms after heavy rains. Turns out, they just might be right.

City leaders said Friday they found a problem with the combined water/sewer overflow system’s Walnut Street outfall while making inspections of drainage system along the Ohio River.

The outfalls carry discharge from the city system into the river.

John Haskins, city wastewater treatment superintendent, said the Walnut Street outfall is submerged and inspectors could not see the end of the pipe, but the nearest manhole to the end of the pipe was inspected and has debris in it, an indication that the pipeline may not be draining properly.

“We can’t say 100 percent that is the problem but we did find a restriction,” Haskins said.

The Walnut Street outfall handles discharge from the south side of the city — the part of town most affected by recent system backups.

The city’s other seven water/sewer outfalls appear to be working properly, Haskins said.

Mike Pemberton, city street department superintendent, said the Walnut Street pipeline will have to be disconnected from the outfall to determine if the pipeline is working properly.

“We need to see how much is draining out of it,” Pemberton said.

City officials said the Walnut Street outfall was likely submerged when the Greenup, Ky., locks and dam were built because the dam raised the level of the river.

Other areas of the city’s system have been inspected in recent weeks and no problems have been found anyplace except the Walnut Street outfall. Haskins said water and sewer systems at Ohio University Southern were inspected this week and appear to be working properly.

Some residents have publicly wondered if recent construction near the campus was to blame for the problems they have experienced.

Since mid-June, some city residents have reported that after hard rains both storm and sanitary sewage has backed up through the plumbing into their basements and bathrooms, leaving several inches to several feet of mess and thousands of dollars in damage.

The issue has been discussed at recent city council meetings and was described by Mayor Rich Blankenship as a top priority.

“We want to keep the public informed about what we’re doing and that we are working to correct the problem,” Blankenship said Friday.

The city had recently agreed to install overflow valves at some homes in the affected area in hopes of preventing the backups from occurring in the future.

The city’s public utilities committee met this week to discuss how and where to install the $6,500-a-piece valves.