Sanitary sewer study could lead to hunt for illegal connections

CEDAR RAPIDS — Don't be surprised if a beefed-up home-inspection effort is in the offing to require homeowners to disconnect sump pumps and foundation drains that are illegally connected to the city's sanitary sewer system.

As part of a pilot study, the Public Works Department has learned that about 25 percent of some 500 homes have the illegal connections in a section of northeast Cedar Rapids generally bounded by Old Marion Road NE, 32nd Street NE, 40th Street NE and First Avenue East.

These connections cause problems as they direct groundwater and stormwater into the city's sanitary sewer system instead of sending it toward the street and the city's separate storm sewer system. The added water during heavy rains like those that hit in late June in parts of Cedar Rapids can help overwhelm the sanitary sewer system and send sewage backing up into basements.

Dave Wallace, sewer utility engineering manager, told the City Council's Infrastructure Committee this week that the preliminary analysis in the study area indicates that the sanitary sewer system there can be forced to take on four or more times the effluent that the system is designed to handle during peak rain events because of 'infiltration and inflow' from connections not allowed by the city ordinance.

This can quickly overwhelm the system, Wallace said.

Wallace said the city selected the study area because it has been a 'problem area' and because most of the houses were built in the 1950s and 60s before the city's connection ordinance was put in place. Any existing connections at the time of the ordinance's adoption were not grandfathered in. They are all illegal, Wallace said.

Sandy Pumphrey, project engineer for flood mitigation, told the committee that the city is taking a close look at the Blake Boulevard SE neighborhood, which experienced significant damage from sewer backups in late June, and he said some homes there have improper connections to the city's sanitary sewer system.

Pumphrey said the city is making three suggestions to homeowners who experienced damage during the heavy rains and flash flooding in late June: Disconnect any sump pump or foundation drain from the sanitary sewer system if there is such a connection; consider purchasing a sewer backflow valve through the city's valve reimbursement program; and consider buying flood insurance.

City Council member Scott Olson, chairman of the Infrastructure Committee, said the city should advise homeowners that the lowest-cost valve might not be the most effective.

Wallace said staffers are working to identify improvements that can be made to the city's part of the sanitary sewer and storm sewer systems, and they are not just looking at illegal connections on private properties.

As part of the sanitary-sewer study, city representatives have visited 487 homes or businesses and have gained access to 145. Nearly all who were home have been cooperative, Wallace said. He said 35 homes entered had a sump pump or foundation drain connected to the sanitary sewer system.

Wallace said the sanitary-sewer system there is designed to handle a peak of about 420 gallons of flow a minute, but the illegal connections potentially increase the flow to between 1,250 gallons to 3,125 gallons a minute.

Not only can sewers backup as a result, but the extra flow in the sanitary-sewer lines also is effluent that makes its way to the Water Pollution Control treatment plant, which increases the city's costs to treat the flow that doesn't belong in the system, he said.

Wallace said the Public Works Department will provide the City Council with an analysis to show what the city's costs might be to expand the size of sewer lines and/or to expand the treatment plant's capacity and what costs there might be for the city to provide some financial incentives to help property owners disconnect sump pumps and foundation drains from the sanitary sewer system.

Olson said the city has identified about 12 major areas of damage following the June rains and flash floods, and Pumphrey said the city had addressed problems in 61 of 128 identified spots. Some of the 67 remaining spots share the same issue, he said.

Olson asked about flash flooding in the 1500 blocks of A and B avenues NE, and Pumphrey said the city found no blockages in sewers there.

Olson said he wanted to make sure the city was tackling easier tasks like cleaning out drainage ditches and silted-in detention basins as it worked to remedy harder-to-fix problems.

The city will have more flash floods, and it needs to be prepared, he said.