“Inflow” and “infiltration,” collectively referred to as I/I, are terms used in the City’s federal Consent Decree to describe stormwater and groundwater entering our separate sanitary sewer systems from the ground through leaky sewer pipe joints, broken sewer pipes and manholes. Other sources of I/I include defective sewer service connections, and from prohibited inflow sources on private property connected to the sanitary sewer system such as foundation drains, down spouts, yard area drains, driveway drains, and stairwell drains.

When I/I enters our separate sanitary sewer system, it flows to a wastewater treatment plant where it is treated and discharged into the Missouri River. When there’s too much stormwater, the separate sanitary sewer system can overflow and send sewage into local creeks, streams, and rivers, harming water quality. Repairing the sanitary sewer system to reduce I/I helps protect our community and the environment by reducing the number of sanitary sewer overflows.

Every gallon of I/I flow kept out of our sanitary sewer systems and treatment plants reduces the potential for sewer overflows and leads to long-term savings on rising utility costs. As part of the Smart Sewer program, KC Water has been working since 2012 to identify I/I sources and taking action to restore our separate sanitary sewer system.

As part of Kansas City’s obligations defined in a Consent Decree with the Environmental Protection Agency (EPA), this work will protect our environment by reducing sanitary sewer overflows into our creeks, streams, and rivers. If I/I is not removed from the separate sewer system, the City will have to spend more money to convey, store, and pump excess wet weather flows through our wastewater treatment system — which is ultimately more costly than I/I reduction measures. Simply put: Less wastewater treatment means less burden on your sewer bill!

KC Water is reducing I/I through both public sewer system and private inflow source disconnection efforts. Public sewer projects include any work being performed on publicly owned sewer assets, such as our Northern Basin Area 1 and Brush Creek Area 2 I/I Reduction projects. For reducing I/I from private property, our Keep Out the Rain (KOTR) program works with property owners to find and fix prohibited inflow connections to the sanitary system at no cost to the property owner.

As an important part of the design process for public I/I reduction projects, smoke testing is often used to find leaky pipe joints, broken sewer pipes and manholes, and prohibited  cross-connections between the separate stormwater system and the separate sanitary sewer system. It involves blowing harmless, artificially produced smoke into the sewer system and seeing where it emerges. If the system is in good condition, the smoke will emerge from only manhole covers and house plumbing system vents on roofs. If the smoke appears anywhere else, there is potential for rainwater and groundwater to enter the sewer system.

Since 2010, targeted I/I reduction projects in our public sanitary sewer systems have been underway to extend their service life and improve their capacity. A total of 21 I/I projects will be completed in the separate sewer system by 2035 as part of the Smart Sewer program.

Repairs to our sanitary sewer system are performed by either open-cut excavation or the use of trenchless technology, such as cured-in-place-pipe (CIPP) and pipe-bursting. These methods often work manhole-to-manhole, which reduces digging and restores our aging sewer system in the most cost-effective, efficient, and minimally disruptive way.

On the private side of I/I reduction efforts, KC Water’s Keep Out the Rain (KOTR) program is working with property owners to address I/I sources on private property. This program, started in 2016, reduces separate sewer system overflows while avoiding more costly sewer system improvements.

KOTR is a voluntary, limited-time program to help residents find and fix prohibited connections at no cost to the property owner. Design professionals (DP) perform 15- to 30-minute evaluations to inspect indoor and outdoor plumbing connections to identify improper connections such as gutter downspouts, floor drains, cap clear outs, and basement drains. If a DP identifies an I/I source that is cost-effective for the team to remove, a property owner agreement is signed, and a plumber is assigned to disconnect the improper source at no cost. These repairs may be small, but they have a substantial impact on the overall health of the sewer system in Kansas City.

To find out if your property is eligible call 816-513-0200 or visit the KOTR project webpage.