Inflow and infiltration (I&I) is storm or ground water that enters into the sanitary sewer system. Inflow water enters the sanitary sewer system through major defects and/or direct connections to the sanitary sewer system. Infiltration water seeps into the sanitary sewer system through cracks, offset joints, or defects in pipes and/or manholes.
Inflow and Infiltration (I&I) can cause the sanitary sewer system to become overloaded beyond the designed capacity of the pipes during a rain event. When the capacity of the pipes is exceeded, the excess wastewater looks for the lowest release point which can result in sewer backups or sanitary sewer overflows which negatively impact residents and the environment. Just a couple of properties with sources of I&I can overload a sanitary sewer line during a rain event.
Common Inflow Sources
- Sump Pumps
- Foundation Drains
- Uncapped cleanouts that are directly connected to the sanitary sewer system.
Common Infiltration Sources
- Offset Joints
- Defects in Pipes
- Defects in Manholes
Problems Caused by Inflow and Infiltration (I&I)
- Basement backups
- Sanitary sewer manhole overflows.
- Increased claims and claim related costs associated with backups.
- Negative impact on the environment due to sewage overflow and contamination.
- Increased costs for utility customers due to storm water being treated at the treatment plant unnecessarily.
- Decreased capacity of the sanitary sewer system.
- Increased costs to upsize pipes for I&I excess peak flows. These projects are expensive and do not completely solve the problem as the excess storm water in the system is still being unnecessarily treated at a cost to the Utility and its customers.
Although you may have I&I connections on your property and never have a problem, your I&I connections could be contributing to a sewer backup in the basement of a neighbor or the overflow of wastewater from a sewer manhole. Any reduction in the amount of storm water or ground water entering the sanitary sewer system is a public benefit to all customers.
How the Water Utilities Department is Reducing I&I
The Water Utilities Department is constantly evaluating and maintaining the public sanitary sewer system. This is accomplished by running a television camera through the pipes to find defects as well as smoke testing, dye testing, jetting, root removal and visual inspections. System repairs, replacements and corrections are made from these evaluations to reduce sources of I&I in the public sanitary sewer system.
You are responsible for ensuring that the private sanitary sewer system on your property is maintained properly to avoid sewer problems on your property and/or properties further downstream on the public system. Your private sanitary sewer system includes all the sewer plumbing on the property you own and your private sewer lateral.
What is a Private Sewer Lateral: The piping that connects a building's internal sewer plumbing to the public sanitary sewer system. The sewer lateral is part of the private plumbing system and is maintained by the property owner.
See Lateral/Service Line for more information.
How You Can Help Prevent Inflow and Infiltration Problems
- Have your private sewer lateral line televised and/or cleaned. Grease and other substances can accumulate over time and cause blockages in the line which can lead to a backup. Laterals can also break at joints and, depending on their location, become infiltrated with roots which can cause the line to clog and create backups. Offset or broken joints and root infiltration also allows opportunities for groundwater to enter into the sanitary sewer system.
- Ensure that any drains that collect storm water discharge to daylight when possible and are not connected to the sanitary sewer system. Discharging to daylight means the drains aren't connected to the sanitary sewer system and are routed to empty at some point outside on the ground. Drainage should be at least 3 feet from the foundation to ensure the storm water doesn't seep into the ground and back into the foundation drains.
- Ensure that your sump pump discharges to daylight at least 3 feet from the foundation. If the sump pump is connected to the sanitary sewer system, have the connection removed and capped and reroute the sump pump to discharge to daylight at least 3 feet from the foundation.*
- Ensure that your gutter downspouts run onto a splash block and drain at least 3 feet away from your foundation. Downspouts can also be connected to underground drain tiles, wet basins, downspout gardens or some other means of moving the water away from the foundation. Gutter downspouts keep water from seeping back into your foundation drains. If your gutter downspouts are connected to the sanitary sewer system, have them disconnected and rerouted at least 3 feet away from your foundation. If your downspouts are connected to a pipe that goes underground and you are unsure of where it drains to, try running a garden hose into the pipe or the downspout to see where the water comes out. If you are still unable to determine where the downspout drains, you can call a plumber to help locate where the pipe goes.*
- Ensure that your sump basin/sump pit discharges to daylight at least 3 feet from the foundation or is connected to a sump pump. A sump basin/sump pit is a pit sometimes found in your basement floor that collects and removes any water that accumulates under the foundation of your home or business. If the sump basin is connected to the sanitary sewer system, have the connection removed and capped; reroute the sump basin/sump pit to discharge to daylight or a sump pump.*
- Ensure that your footing or foundation drains discharge to daylight at least 3 feet from the foundation or are connected to sump basins/sump pits. Footing or foundation drains surround the foundation of your home or business and provide for the removal of ground water from around your foundation. They are sometimes connected to sump basins or sump pits for the removal of collected ground water. If the footing or foundation drains are directly connected to the sanitary sewer, have them disconnected and rerouted to daylight or a sump basin/sump pit.
- Ensure that your outdoor stairwell drains discharge to daylight at least 3 feet from the foundation if the grade of the landscape allows. If the grade does not allow discharge to daylight, connected to a sump basin/sump pit. Outdoor Stairwell Drains are located at the bottom of an outdoor, non-enclosed stairwell. If the outdoor stairwell drains connect to the sanitary sewer system, have them disconnected and rerouted to daylight or a sump basin/sump pit. *
- Ensure that your driveway or area drains discharge to daylight at least three feet from the foundation if the grade allows. If the grade does not allow discharge to daylight, connected to a sump basin/sump pit. Driveway or Area Drains are sometimes found in driveways, patios or other outdoor surfaces where water can accumulate because of low spots. These types of drains should discharge to daylight whenever the grade of the landscape allows. If the driveway or area drains are connected to the sanitary sewer system, have them disconnected and rerouted to daylight or a sump basin/sump pit.*
*Contact the Lee's Summit Codes Administration Department for any necessary permits before proceeding with any plumbing work.