Milwaukee is served by two sewer systems: the combined sewer system and the separate sewer system.

• In a combined sewer system, wastewater (sanitary sewage) and stormwater enter one pipe where it is sent to the wastewater treatment facilities. A majority of the water running through this system comes from stormwater runoff and groundwater entering the system.

• In a separate sewer system, wastewater and stormwater enter two separate pipes. The storm sewer collects stormwater runoff and groundwater entering the system and carries it directly to a local waterway and, ultimately, Lake Michigan. The sanitary sewer system sends water to wastewater treatment facilities.

View a diagram of the sewer system.

The separate sewer system.

The sanitary sewer system is smaller than the storm sewer and carries only wastewater from sources like sinks and toilets. Increases in the water to the sanitary sewer due to infiltration and inflow can cause the system to over fill, increasing the risk of home backups.

• Infiltration occurs underground and out of sight as clear water entering the sanitary sewer system through defective and aging pipes, pipe joints, and lateral connections.

• Inflow is clear water entering the sanitary sewer system through direct connections such as foundation drains, sump pump discharges, and downspout connections.

ALL sources of inflow and infiltration have to be addressed in order to reduce the amount of water that flows into the neighborhood and causes basement backups for some neighbors. Further, the pipes in Grasslyn Manor are continuing to age and reach the limit of their useful life. This project is an opportunity to replace aging infrastructure, potentially for free.

No, these are non-assessable improvements that will not raise your taxes.

Property owners own the pipe from their home all the way to the sewer main, including the point of connection. Homeowners are responsible for maintenance of their plumbing systems.

View a diagram of sewer pipe ownership.

Investigations will take place during the summer of 2025 with repairs planned to begin in summer 2026.

Sewer lateral replacement can cost between $20,000-$25,000 and sump pump replacement and installation can cost a minimum of $5,000.

Your home failed, or test results were inconclusive in a series of tests performed by DPW. The recommended improvements will help reduce the risk of basement backup events and sewer overflows.

You will need to be home to let the contractor into your home in the morning. You are welcome to remain at your home while work is being performed, or you are welcome to leave and return home after work is complete.

Steps are taken to reduce mess inside and outside of the home, including tarps and the use of hammer drills to minimize dust. The contractor will restore concrete, pavement, sidewalk, and grass to its previous state at the end of work.

The program will cover the cost of replacing your sanitary lateral, replacing your lead service line, installing a sump pump, and/or disconnecting your downspout. You may incur the cost of restoring ornate landscaping or finishes in your basement after the completion of construction.

While not an exact science, DPW estimates that the plastic laterals installed with this program have a 50-year lifespan.

During the replacement of the sanitary lateral and the lead service line, the property will be without water for the day while work is being performed.