Project of the Week: How CIPP work protects our sewer system

Cedar Rapids' sanitary sewer system features nearly 700 miles of pipes, some of which are more than 100 years old. How does the City keep such a large network working properly?

Thanks to projects like the FY2026 sewer lining program, City workers are patching age-related gaps in the system. Their work protects residents from backups and maintains the system's ability to transport wastewater to the Water Pollution Control facility.

Inflow and infiltration

Inflow and Infiltration make the system's job harder.

Inflow happens when stormwater enters the sanitary sewer system through direct connections like sump pumps, foundation drains, storm sewer connections, and openings in manhole lids. Meanwhile, infiltration happens when groundwater enters the system through defective joints or cracks, holes and faulty connections.

Excess stormwater entering the sewer system can cause basement sewer backups, overflows into the environment, and strain the capacity for water treatment. To address this concern, the City uses Cast In Place Pipe (CIPP) liner. That liner can block leaks, fill cracks and seal up the ends of each pipe segment.

Cedar Rapids has been using CIPP for sewer repairs since 1971.

"The biggest advantage is that the process is pretty quick and has minimal impact on homeowners and on the environment," says Project Engineer Loren Snell. It also has a significant reduction in costs and impacts to traffic, as compared to full pipe replacement.

The City's CIPP work in 2026 consists of 113 sewer lines scattered around all four quadrants. "Most of these sites are on residential streets that will have minimal impact on traffic and homes," Snell says. "But there are a few more significant sites on Mt. Vernon Rd SE, C Avenue NE by Blairs Ferry Rd, Collins Road NE east of Center Point Road, 42^nd St NE, and 1^st Avenue East."

The process of installing the liner involves placing a felt tube into an existing sewer pipe. Once in place, the tube is inflated to fit tightly inside the original pipe. Then it hardens, or cures, in order to create a new plastic pipe within the old pipe.

During the installation process, residents may see a steam cloud coming from the manhole, It will dissipate quickly once the process is complete.

Workers are at each site for about two days. The first visit is for cleaning and pre-televising of the city sewer, where a camera is used to record home service locations and defects. Next, workers install the liner and reinstate the home taps into the city sewer main.

The liner is made up primarily of a felt/plastic tube and styrene resin, a clear, colorless liquid that is synthesized for commercial use from petroleum and natural gas byproducts.

Curing the solution

The curing process creates a glue-like odor that is usually harmless in normal concentrations but can be unpleasant. The smell is caused by the drying and curing of the resin that hardens the soft liner into a hard lined pipe. The scent can enter homes if taps are dry in the home.

In order to prevent sewer odors such as this pipe resin from entering homes, residents are encouraged to regularly pour about a gallon of water into floor drains and other less frequently used drains. The water will sit in the drain trap, blocking odors from getting into the home.

Overall, CIPP lining is a very cost effective, lower-impact method of improving the City's sanitary system. As this year's installations continue, they strengthen residents' protection from sewer backups and flooding. You can learn more about the City's efforts to protect against inflow and infiltration here.

Project of the Week puts a spotlight on work happening all over the City every day. Each week, we will take a closer look at projects that are investing in our community's roads, trails, Flood Control System, and more. See previous installments here:

July 30: 6^th Avenue SW from 1^st Street to 2^nd Street
July 24: 4^th Street Trail Extension
July 17: 12^th Street SE/Coe Road
July 10: 34^th Street SE
July 3: Roundhouse
June 25: Mount Vernon Road
June 18: Grande Avenue SE
June 11: O Avenue NW Time Check Elevation Project
June 5: Nassau Street
May 28: Cedar Lake
May 21: Tree of Five Seasons Park
May 14: 20th Street NW
May 7: 18th Avenue SW
April 30: Alliant Energy LightLine™
April 23: 42nd Street
April 16: The 3rd Avenue Bridge