Inflow and Infiltration (I&I)
The Lee's Summit Sanitary Sewer System is designed to carry wastewater from homes and businesses and convey that wastewater to the Little Blue Valley Wastewater Treatment Plant. When storm and/or ground water enters the system through inflow and infiltration (I&I), the sanitary sewer system can become overloaded and potentially result in sewer backups or sanitary sewer overflows which negatively impact residents and the environment. Typical sources of I&I include cracked pipes as well as sump pumps, downspouts and foundation drains that have been directly connected to the sanitary sewer system. By working together, the customers of Lee's Summit Water Utilities and the Water Utilities Department can reduce sources of I&I and help protect the environment from sanitary sewer backups and overflows as well as keep fees, sewer system costs, and treatment costs down.
Any drains that collect storm water (sump pumps, sump basins, outdoor stairwell drains, driveway drains, gutter downspouts, etc.) should drain onto the ground whenever possible, at least 3 feet from the foundation. These types of drains should never be connected to the sanitary sewer system. Discharging to daylight means the drains aren't connected to the sanitary sewer system, but instead are routed to empty at some point outside on the ground. These type of drains need to discharge at least 3 feet from the foundation to ensure the storm water doesn't seep into the ground and right back into the foundation drains.
Inflow is storm or ground water that enters into the sanitary sewer system through direct connections or major defects. Common sources of Inflow are sump pumps, foundation drains, downspouts and uncapped cleanouts that are directly connected to the sanitary sewer system.
Infiltration is storm or ground water that seeps into the sanitary sewer system through cracks, offset joints, or defects in pipes and/or manholes.
Inflow and Infiltration is commonly referred together as I&I.
A private sewer lateral is a sewer pipe 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.
The Sanitary Sewer is a system of pipes and devices that are designed to carry sanitary sewer, or wastewater, from approved drains in homes and businesses such as sinks, toilets, and showers, to a wastewater treatment plant.
The Storm Sewer is a system of pipes and channels designed to carry storm and ground water from streets, parking lots, roofs, driveways, sidewalks, etc., directly to drainage creeks, rivers and/or detention basins.
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The Lee's Summit sanitary sewer system is designed to carry wastewater from residences, businesses and industries throughout the City to the Little Blue Valley Sewer District for treatment. Only approved drains that are protected from storm and ground water should drain to the sanitary sewer system. The system is designed with the appropriate sized pipes to handle the removal of wastewater only, and does not have the capacity to handle additional water from storm and ground water sources. The sanitary sewer system is constantly evolving to accommodate the removal of wastewater from existing and new development. The sanitary removal of wastewater provides for a healthier environment and better quality of life.
The storm sewer system is designed to carry storm and ground water directly to natural drainage features such as creeks, streams, rivers and/or lakes. This system is designed with much larger capacity pipes and drainage features to handle large volumes of water from rain, snow melt and ground water sources. Storm and ground water is clear water that does not need treatment before entering a natural drainage feature.
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During significant rain events, storm and ground water can find its way into the sanitary sewer system through Inflow and Infiltration. When this excess water enters the sanitary sewer system, it can create the following problems:
- I&I can increase the flow in the sanitary sewer system to a point beyond the designed capacity of the pipes. When the capacity of the pipes is exceeded, the excess wastewater looks for the lowest release point which can lead to basement backups and/or sanitary sewer manhole overflows.
- Storm and ground water that enters the sanitary sewer system is transported to the treatment plant and unnecessarily treated. This leads to higher treatment costs for the utility and its customers.
- If I&I are not addressed, the sanitary sewer pipes may have to be upsized to handle these peak flows to reduce backups and overflows. 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.
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Depending on the type of I&I connection(s), just a couple of properties with sources of I&I can overload a sanitary sewer line during a rain event. When the line becomes overloaded, the wastewater looks for the lowest point to release the pressure building up in the pipe. This can be a basement drain or a sewer manhole. Although a property owner may have I&I connections on their property and never have a problem, they could be contributing to a sewer backup in the basement of a neighbor or the overflow of wastewater from a sewer manhole. Removing sources of I&I can help to reduce the occurrences of backups and overflows. Any reduction in the amount of storm water entering the sanitary sewer system is a public benefit to all customers of the Lee's Summit Water Utility. The benefits include:
- Decreased occurrences of basement backups
- Reduced claims and claim related costs associated with backups
- Better protection of the environment from the impact of overflows
- Reduced treatment costs
- Increased capacity of the sanitary sewer system
- Reduced need for expensive projects to handle excess flow
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The public sanitary sewer system includes all pipes, manholes, pumping stations, excess flow holding basins, etc., in the system, up to the point where the customer's private sewer lateral connects to the public system. The Lee's Summit 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.
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The private sanitary sewer system includes all the sewer plumbing in a property owners home or business and includes the sewer lateral from that home or business to the point of connection with the public sanitary sewer system. The property owner is responsible for ensuring their private sanitary sewer system is maintained properly to avoid sewer problems on their property and/or avoid contributing to problems for property owners further downstream on the public system.
Click image to enlarge.
What to look for:
- Have your private sewer lateral 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.
- If you have a sump pump in the basement, ensure it is discharging to daylight (out to the yard or away from the home) and not directly connected to the sanitary sewer system. 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. Contact the Lee's Summit Codes Administration Department for any necessary permits before proceeding with any plumbing work.
- Gutter downspouts should run onto a splash block and drain at least 3 feet away from your foundation to keep the water from seeping back into your foundation drains. 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. Downspouts should never be connected to the sanitary sewer system and should be disconnected if they are found to be so. 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 at. If you are still unable to determine where the downspout drains, you can call a plumber to help locate where the pipe goes.
- A sump basin 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. A sump basin should discharge to daylight or have a sump pump to discharge collected water outside to an area at least 3 feet from the foundation. A sump basin should not be directly connected to a sanitary sewer line or have a sump pump that discharges to a sanitary sewer line. If the sump basin and/or sump pump is connected to the sanitary sewer system, have the connection removed and capped and reroute the sump basin and/or sump pump to discharge to daylight at least 3 feet from the foundation. Contact the Lee's Summit Codes Administration Department for any necessary permits before proceeding with any plumbing work.
- Footing or Foundation Drains surround the foundation of your home or business and provide for the removal of ground water from around your foundation. Foundation drains are sometimes connected to sump basins or sump pits for the removal of collected ground water. Foundation drains should never be connected to the sanitary sewer system. Foundation drains that are directly connected to the sanitary sewer should be disconnected and rerouted to daylight, a sump basin or a sump pit. If the foundation drain is connected to, or rerouted to, a sump basin or sump pit, ensure the sump basin or pit is not connected to the sanitary sewer as described in items 2 and 4 above. Contact the Lee's Summit Codes Administration Department for any necessary permits before proceeding with any plumbing work.
- Outdoor Stairwell Drains are located at the bottom of an outdoor, non-enclosed stairwell and should discharge to daylight if the grade of the landscape allows. If the grade isn't low enough for this type of drainage, then the stairwell drain may need to be connected to a sump basin or sump pit that discharges to daylight or has a properly draining sump pump as described in Items 2 and 4 above. Out door stairwell drains should never be connected to the sanitary sewer system. Contact the Lee's Summit Codes Administration Department for any necessary permits before proceeding with any plumbing work.
- 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. These types of drains should never be directly connected to the sanitary sewer system. If the grade does not allow for these drains to discharge to daylight, then the driveway or area drain should be connected to a sump basin or sump pit that does discharge to daylight or has a properly draining sump pump as described in items 2 and 4 above. Contact the Lee's Summit Codes Administration Department for any necessary permits before proceeding with any plumbing work.
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For questions, please call 816-969-1930