The city of Austin will start work on a rising problem this summer.

Sewer Department workers will be busy over the next five years testing and rebuilding manhole covers, inspecting all 120 miles of the city’s aging sewer system, and hopefully reducing the amount of groundwater going into the Wastewater Treatment Plant.

“It’s a slow process,” said Assistant City Engineer Steven Lang. “There are a lot of sewer lines in the system.”

A manhole replacement program and inflow & infiltration reduction program are two of several sewer projects budgeted under the city’s five-year Capital Improvement Plan.

City officials say more of the city’s 1,500 or so manholes are allowing too much groundwater to infiltrate sewer systems, which increases the water flow at the treatment plant to the point where it exceeds the plant’s flow capacity.

Finding and rebuilding older manholes will save the city treatment plant costs, according to the CIP.

Lang said sewer workers will be looking for manholes and inspecting sewer lines while the city pursues street reconstruction projects every summer. To that end, the city has budgeted $25,000 annually for the next five years to fix manholes, with $50,000 in total budgeted for sewer line inspection and I & I work.

Workers face a daunting task, as some of the city’s sewer lines are approaching 100 years old. The city’s wastewater treatment plant started in the early 1900s, according to Lang, with an expansion and upgrades taking place in the 1930s. That means much of the sewer system in downtown Austin and surrounding areas are decades old, and Lang said during a 2011 street project city workers found some sewer lines estimated to be from the 1920s.

“In general they’re in very good condition for their age,” Lang said concerning the city’s manholes and sewer lines.

As time flows, however, leaks and malfunctions are appearing in manhole casings and in some sewer lines, particularly near the Cedar River’s flood plain, which workers take care of as problems arise. The CIP project calls for workers to develop a plan to reduce I & I throughout the city, starting with the lines and manholes near scheduled street projects.

“To start the project, we’re taking the approach of working to correct our system,” Lang said.

Once the city’s sewer infrastructure has been inspected and maintained, the city will make a concerted move to inspect all private lines and plumbing.