Sump Pump Inspection Program

Based on an Engineering study completed in 2004, each year many gallons of storm water improperly drain into the Lake Mills public sanitary sewer system. This contributes to overloading the sanitary sewer system, which may cause back-ups and health related issues. The study indicated that an increase in rain induced flows seem to be caused primarily by various illegal connections. An illegal connection is a connection that permits extraneous storm-related water to enter the sanitary sewer system. The extraneous storm-related water is water that should be going to the storm sewer or allowed to soak into the ground without entering the sanitary sewer.
Infiltration/Inflow (I/I) is the term used to refer to the extraneous water entering the sanitary sewer system through broken pipe joints, leaky manholes, improper heights of sewer vent stacks, illegally connected roof and foundation drains, clean-outs located in yards or parking areas, sump pumps or through cross-connections with storm sewers. In addition, defective house sewer lines cause extraneous water to enter the sanitary sewers and, thus, they are also illegal connections.
The sanitary sewers have been designed to transfer sanitary waste only. Extraneous storm-related water flow added to the normal sanitary flow can exceed the capacity of the sanitary sewer resulting in a situation where the sanitary sewer is "surcharged." Basically, surcharging occurs when the amount of flow trying to get through a pipe exceeds the maximum capacity of the pipe thus building up pressure in the pipe. When pressure builds up, it seeks to relieve itself through any means possible; one of which is by backing up into private sanitary services and filling basements and crawlspaces. Reducing the extraneous flow will reduce the future potential of surcharging and sewer back-ups. Sump pump inspections are one of the easiest and most effective methods for removing substantial amounts of extraneous storm-related water from the sanitary sewer system.
Sump pump systems are designed to capture surface or ground water that enters basements or crawl spaces and pump it away from the house. The basic sump system includes drain tile, a sump pit, a sump pump, a float or switch, and a drain line. The sump pit extends below the slab and collects surface water that enters the basement/crawl space or groundwater that rises to the slab.
Homeowners commonly use sump pumps in their basements to battle moisture and flooding issues. However, water from sump pumps should NOT be discharged into the sanitary sewer system. That’s called a cross connection, and it results in higher sanitary sewer costs. Often, this is a hose leading from the sump to a laundry tub or a floor drain. As you may know, water that goes down any drain in your house leads to the sanitary sewer system and eventually ends up at a wastewater treatment plant, where it is treated before being released back into the environment. Sump pump water is what engineers call "clear water"-most often rain water, ground water, or snow melt. This water should flow directly into area streams, ponds, and lakes. Water from sinks, showers, tubs, toilets, and washing machines is wastewater and must be treated before it is discharged into the environment.
Extraneous storm-related water/clear water, such as that from a sump pump, overloads the sanitary sewer system. During the rainy season (April through October), this clear water increases the flow through Lake Mill’s sanitary sewer system one to two times the usual amount and sometimes higher, primarily because of cross connections. Since the number of gallons of clear water flowing through the City sanitary sewer collection system is being treated, clear water is costly.
Surcharging may result in sanitary sewer overflows (SSOs) which are discharges of untreated sewage from city sanitary sewer systems as a result of extraneous storm-related water from inflow and infiltration. Combined sewer overflows (CSOs) are discharges of untreated sewage and stormwater from municipal sewer systems or treatment plants that combine sewage and stormwater when the volume of flow exceeds the system’s capacity due to periods of heavy rainfall or snow melt.
Although sewage is very unsanitary, the term "sanitary sewer" is used because the sewer pipes are separate from the pipes used for storm water drainage. This helps protect public health and the environment. In some older cities, sewage and rainwater flow through the same pipes. This can cause major environmental and public health problems because untreated or partially treated-sewage is discharged into streams, rivers and other water bodies during heavy rain.
Sewage spills are technically called "sanitary sewer overflows" since it involves the overflow of sewage from the sanitary sewer system. The word "sanitary" is used only because the overflow is from the sanitary sewer system, and not because the raw sewage is sanitary. Sewage overflows often occur from sewer manholes in the streets. Sewage can also backup into homes through toilets, showers and floor drains. Sewage spills are caused by sewage filling the sewer pipes behind the clog or from surcharging to the point where it spills out of an opening in the system (generally the lowest manhole, shower drain or other plumbing fixture).
In response to U.S. Environmental Protection Agency regulations, local governments, including Lake Mills, have adopted ordinances prohibiting the intrusion of extraneous storm-related water into sanitary sewers. Many homes have sump pumps. The water pumped should be directed to the yard or a French drain, not into the sewer system. It is a violation of City and Town Codes to have such a hook-up. A sump pump can generate as much as 36 gallons per minute. If it is connected to the sewer system, you can easily see how a few illegal connections can increase the flows in the system. For example, an eight-inch sanitary sewer can handle domestic water flow from up to 465 homes; however, it takes only twelve sump pumps operating at full capacity to overload an eight-inch sanitary sewer. Reputable plumbers are aware that sump pump connections to the sewer system are illegal, but occasionally a home handyman will solve the drainage problem by connecting the sump pump flow directly to the sewer system without realizing the consequences.
A good sump pump inspection program can be the most cost-effective method of locating and fixing extraneous storm-related water intrusion into the sanitary sewer system and reducing flows for treatment at the Wastewater Treatment Plant.
The sump pump program has to be modified to meet new ordinance requirements of only regional inspections based on evidence. The City is in the process of installing a new SCADA system that will help provide the information needed to generate the evidence needed to have Council authorize some regional inspections. Hopefully, the spring flows will generate enough data to identify specific areas that need inspection and the Council will approve the hiring of an inspector.