Workers upgrade the Derek R. Guthrie Regional Water Quality Treatment Center. | Courtesy of the Louisville/Jefferson County Metropolitan Sewer District

Monthly sewer bills in Jefferson County will jump $10.49, or by about 24 percent, under a proposal to spend $4.3 billion over the next 20 years to repair critical infrastructure to prevent flooding and waterway pollution.

Tony Parrott

Tony Parrott, director of the Louisville/Jefferson County Metropolitan Sewer District, will present the proposal at 4 p.m. Monday before the Metro Council Budget Committee at council chambers, 601 W. Jefferson St.

MSD officials told Insider that the funds the department normally used to repair and maintain its aging infrastructure, some of which dates to the Civil War era, had been used for other major projects required to get into compliance with the federal Clean Water Act and other laws.

The federal government had sued MSD in 2004, accusing the system of violating federal laws by allowing untreated sewage to enter local waterways.

Since the late 1950s, sewage has been transported from homes and businesses to wastewater treatment plants, but during heavy rains, rainwater mixes with the sewage, and the combined amount of fluid sometimes threatens to overwhelm the pipes and treatment plants.

In those cases, some of the sewage and water mixture traditionally has been allowed to overflow — untreated but diluted — into rivers and streams. In the 1970s, federal regulators said that practice could no longer be allowed and began requiring municipalities to address the problem to keep waterways clean and improve public health.

An agreement between the feds and MSD required the sewer district to expand and improve its infrastructure to significantly reduce such overflows.

Parrott told Insider that the district had completed $400 million worth of projects, but had to spend $500 million more through 2024.

“That’s a federal requirement. We have to do that,” he said.

The improvement projects included the construction of large basins to expand the system’s capacity to hold the rainwater and sewage mixture to prevent treatment plants from being overwhelmed and to prevent overflows.

For example, the seven-million-gallon Clifton Heights basin was expected to reduce the number of overflows in a typical year from 127 to six. The district also plans to build a 2.7-mile, 24-foot-diameter tunnel, 200 feet underground, to store additional effluent in heavy rain events. Construction on that tunnel, which will be built instead of three storage basins, is scheduled to begin this summer.

Those kinds of investments, Parrott said, have prevented the district from completing critical repair and maintenance projects, even though city government has allowed MSD to increase its rate up to 6.9 percent annually.

“We have been sort of using a band-aid approach to … keep the system running,” he said.

Deferred maintenance increasingly is leading to failing infrastructure, which is costly to fix, officials said. The district has dealt with cave-ins on Broadway four times in the last five years, requiring repairs that cost about $500,000 each.

With input from the community, MSD has generated a Critical Repair and Reinvestment Plan that outlines the most pressing steps needed to reduce neighborhood flooding and upgrade the infrastructure to prevent more cave-ins and flooding from the Ohio River.