CEDAR RAPIDS, Iowa (KCRG-TV9) -- The City of Cedar Rapids will begin a series of smoke tests of the sanitary sewer system today.
The purpose of a smoke test is to find breaks and defects in the sanitary sewer system.
During the test, smoke should exit through vent stacks on homes. This is normal, as the vent stacks are designed to vent sewer gases to the atmosphere.
During the tests, staff and contractors will be looking for smoke exiting the sewer system through unexpected places like downspouts, foundations, in yards and possibly storm sewer inlets.
Smoke exiting through these locations indicate a problem that contributes to rain and groundwater entering the sanitary sewer system.
The tests will last three to five days and are being conducted as part of the Inflow and Infiltration Study investigating the problem of excess water entering the sanitary sewer system.
Inflow happens when stormwater goes into the sewer system through direct connections like sump pumps, foundation drains, storm sewer connections and openings in manhole lids.
Infiltration occurs when groundwater enters the sewer system through defective joints or cracks in the sewer pipes.
Inflow and infiltration can quickly overwhelm the capacity of the sanitary sewer system during extreme rain events, causing basement backups and sewer overflows.
The excess flow also strains the capacity of the Water Pollution Control Facility.