Waukesha County, Wisconsin · Waukesha
Water spreading, a burst pipe, sewage, mold or smoke? Call to be connected with a restoration company that serves Waukesha, Brookfield and New Berlin. Start the steps below while you wait.
Answered 24/7 by a participating local provider. We're a referral service and don't do the work ourselves. How it works
Start here
Pick the closest match. These steps limit the damage and protect your insurance claim. Skip anything that isn't safe.
Waukesha County averages 56 nights a year at 20°F or colder, mostly November to March, and 20% of its homes predate 1960.
Basements flood here mostly in June. Waukesha County averages 5.9 days a year with an inch of rain or more.
Backups often follow heavy rain, which Waukesha County gets about 5.9 days a year, when storm water overloads sewer mains and pushes up through the lowest drain in the house.
Roof leaks here come from summer downpours and, with about 92 freeze-thaw days a year, from winter ice dams. Most show up as ceiling stains in the room below.
2% of occupied homes in Waukesha County heat mainly with wood or propane, below the Wisconsin county median of 32.9%.
About 15 nights a year here stay at 65°F or warmer, so basements and crawl spaces can grow mold even without a leak.
Local risk profile
Waukesha County covers 550 square miles of southeast Wisconsin, with about 411,762 residents and 175,591 homes. Waukesha is the county seat; Brookfield, New Berlin and Menomonee Falls are the next largest communities. The county's median home was built in 1981.
24/100 Water Damage Risk Index: Lower Waukesha County ranks 71 of 72 Wisconsin counties. See the statewide ranking and method.The three factors where Waukesha County ranks highest compared with other Wisconsin counties.
Waukesha County is milder than most of Wisconsin, but not mild enough to skip winterizing. From 2015–2024 it averaged 56 nights a year at 20°F or colder, the range where pipes in exterior walls, crawl spaces and unheated garages freeze, and 139 nights at or below 32°F. That ranks 66th of 72 counties.
The longest cold spell was straight 23 days without the temperature rising above freezing, ending in March 2015. The coldest night reached about -27°F on January 31, 2019. Burst pipes usually show up when a spell like that breaks and the ice thaws.
Most freezing nights fall from November to March, peaking in January. Disconnect garden hoses and shut off outdoor spigots before the first hard frost, and keep the heat at 55°F or higher if you'll be away.
On average the first fall freeze arrives around Oct 18 and the last spring freeze around May 3.
Rainfall is about average for Wisconsin. About 5.9 days a year bring an inch or more (44th of 72), most often in June, out of 36.7 inches of total precipitation. On September 12, 2022, 5 inches fell in a single day. Multi-day storms matter most for basements; the wettest three days on record here totaled 6.01 inches (through September 13, 2022).
Freeze-thaw days, below freezing overnight and above it by afternoon, come about 92 times a year here. They're the main driver of ice dams and of water working its way through foundation cracks in late winter.
Housing
48% of homes in Waukesha County predate 1980, below the Wisconsin county median of 54.1%, which ranks 58th of Wisconsin's 72 counties.
The mix runs from 20% built before 1960 to 22% built since 2000, so older neighborhoods bring aging pipe while newer subdivisions bring failed appliance lines and water heaters.
30% date from 1980 to 1999, the window when polybutylene, a gray flexible plastic supply pipe, was used in some homes. It's prone to leaks at the fittings, so it's worth checking for in a house from those years.
Beyond water
About 15 nights a year in Waukesha County stay at 65°F or warmer, a sign of muggy summer air (24th of 72 counties). June is the wettest month. Keep indoor humidity under 60%, as the EPA advises, and dry any leak within 24 to 48 hours; in a humid month a wet basement left alone won't dry by itself.
Mold remediation: what to expectHeating fuel matters for fire risk. In Waukesha County it's 77% utility gas, 18% electric, 2% propane and under 1% wood. Fires here are likelier to start in the kitchen or the wiring than in the furnace. After any fire, keep the HVAC off until ducts are checked, or soot will travel through the house.
Fire and smoke cleanup: first stepsCoverage
Calls connect to restoration companies that work across Waukesha County. The largest communities by population:
Population from ACS 2020-2024 5-year estimates. Townships and unincorporated areas are covered too.
Nearby
Dodge, Jefferson and Washington get more pipe-freeze nights than Waukesha. Milwaukee County has the oldest housing nearby, with 79% of homes built before 1980.
By the numbers
| Factor | Waukesha | Wisconsin median | Rank |
|---|---|---|---|
| Homes built before 1960 | 20% | 31% | 68 of 72 |
| Homes built before 1980 | 48% | 54% | 58 of 72 |
| Homes built 2000 or later | 22% | 21% | 31 of 72 |
| Manufactured or mobile homes | 0.6% | 4.8% | 70 of 72 |
| Vacant homes | 3.9% | 12% | 66 of 72 |
| Wood or propane heat | 2.3% | 33% | 71 of 72 |
| Nights at 20°F or colder | 56/yr | 73/yr | 66 of 72 |
| Days with 1 inch+ of rain | 5.9/yr | 6.3/yr | 44 of 72 |
| Freeze-thaw days | 92/yr | 94/yr | 44 of 72 |
| Muggy nights (65°F+) | 15/yr | 11/yr | 24 of 72 |
Rank 1 is the highest value. Bars run from the lowest to the highest Wisconsin county; the tick marks the median; orange means higher water damage risk than the median, green means lower.
Questions
Peak risk months in Waukesha County: freezing from November to March, heavy rain in June, August and October.
Sources: U.S. Census Bureau, ACS 2024 5-year estimates (2020-2024); weather from NOAA nClimGrid-Daily county averages (EpiNOAA), 2015–2024, averaged across the county; county boundaries from Census TIGER. Reviewed 2026-10-21. Methodology