About Us
2035 Vision
Strategic Plan & Performance
Research
History
Milorganite
GIS Maps and Data
News
Events
Facilities
Budget/Financial
Blue Notes Newsletter
Blue Notes Newsletter Sign-up
What We Do
Education and Outreach
Milwaukee Estuary AOC Projects
Sustainability
What You Can Do
Green infrastructure
Rain Barrels
Rain Garden
Porous Pavement
Native Landscaping
Adopt-A-River
Become a Fresh Coast Guardian
Home HazMat Collection
Medicine Collections
Water Drop Alert
What Not to Flush
Procurement
Procurement Opportunities
Construction and CAD Standard Documents and Special Bid Attachments
Vendor Registration
Events & Outreach
Supplier Development
Business Capacity Development
Workforce Development
Contract Compliance Login
Government & Business
Municipal Information
Rules & Regulations
Private Property I & I
Pipe Check Contractor Resources
Industrial Waste & Pretreatment
Total Maximum Daily Loads (TMDL)
2050 Facilities Plan
2020 Water Quality Initiative
Share This
The Milwaukee Metropolitan Sewerage District (MMSD) is reporting the following information (see 5-day letter) to the Wisconsin Department of Natural Resources regarding sewer overflows that occurred due to historic rainfall and flooding on August 9 through August 10, 2025.
Since 1995, MMSD has designed and constructed $585 million in flood management projects, including Lincoln Creek, County Grounds, Hart Park, Valley Park, and Pulaski Park, to name a few. All those projects provided levels of protection during the devastating storms that just occurred. Without those projects, damage in the region would have been much worse. MMSD has an additional $712 million in future flood management projects to get done, with significant work needed in the Kinnickinnic River Watershed, where there are 660 structures at high risk for flooding.
5-Day Letter to WNDR
View Water Reclamation Facilities Current Capacity
Record rainfall in the Greater Milwaukee area on August 9 and 10, 2025, resulted in life-threatening flash flooding, property damage, and overflows from local and regional sewer systems. MMSD received over 1,100 reports of water backing up into basements.
According to the MMSD area-wide rain gauges (see map below), 14 areas received seven inches or more of rain in 24 hours. To illustrate the scale of this event, one inch of rain across our service area is equivalent to 7.1 billion gallons of water.
8/9/25 - Combined Sewer Overflow and Sanitary Sewer Overflow: 5.14 billion gallons
One inch of rain in MMSD's service area equals 7.1 billion gallons of water.
To view a map of the impacted waters from the sewer overflow in the Greater Milwaukee area.
Wait for the water to drain out of the basement before entering. Or, call a qualified electrician to disconnect the power before you enter a flooded basement.
Call your municipal public works department to report local flooding, and call your homeowners/renters insurance agent.
Please fill out the "Report a Basement" form to help track flooding in our area, which is shared with the 29 municipalities MMSD serves.
Report a Wet Basement
Stay out of floodwater — it may have sewage, chemicals, or trash. Never walk or drive through floodwater. Wear boots and gloves for cleanup, and wash your hands after.
Food Safety After Flooding. Throw away any food, drinks, or medicine that has come into contact with floodwater. Toss food in packages that are wet or damaged. Wash and sanitize dishes, utensils, and counters that came into contact with floodwater.
Receive Water Drop Alert text messages when heavy rain threatens the area. When a Water Drop Alert has been issued, a reminder is sent to use less water.
What do you do when an alert is issued?
Please be safe around our concrete-lined rivers. STAY OUT of the concrete-lined channel since the water is fast-moving and the concrete is slippery. Call 911 if someone is in danger. We need your help in keeping our community safe.
By using our website you are consenting to our use of cookies in accordance with our cookie policy.