St. Charles County, Missouri · St. Charles
Water spreading, a burst pipe, sewage, mold or smoke? Call to be connected with a restoration company that serves O'Fallon, St. Charles and St. Peters. 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.
Pipes freeze in St. Charles County on about 25 nights a year, mostly December to February. Older homes, 7% of the stock here, are most at risk.
April brings the most downpours to St. Charles County, part of 10.5 heavy-rain days a year. Check the sump first.
7% of homes here predate 1960, when clay and cast iron sewer laterals were standard. Roots and cracks in those lines are a common cause of backups.
St. Charles County's wettest day in the 2015–2024 record brought 4.96 inches, and about 71 freeze-thaw days a year mean ice dams in some winters.
4% of occupied homes in St. Charles County heat mainly with wood or propane, below the Missouri county median of 24.5%.
About 72 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
St. Charles County covers 561 square miles of eastern Missouri, with about 414,535 residents and 167,163 homes. The county seat is St. Charles, and O'Fallon, St. Peters and Wentzville round out the largest towns. Much of its housing is recent, with a median build year of 1994.
38/100 Water Damage Risk Index: Moderate St. Charles County ranks 101 of 114 Missouri counties. See the statewide ranking and method.The three factors where St. Charles County ranks highest compared with other Missouri counties.
Pipe-freeze risk in St. Charles County sits near the middle of the state. From 2015–2024 it averaged 25 nights a year at 20°F or colder, the range where pipes in exterior walls, crawl spaces and unheated garages freeze, and 86 nights at or below 32°F. That ranks 66th of 114 counties.
The longest cold spell was straight 14 days without the temperature rising above freezing, ending in January 2018. The coldest night reached about -7°F on January 15, 2024. Burst pipes usually show up when a spell like that breaks and the ice thaws.
Most freezing nights fall from December to February, 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.
Freezing nights typically start around Nov 1 and end around Apr 8.
Rainfall is about average for Missouri. About 10.5 days a year bring an inch or more (52nd of 114), most often in April, out of 43.7 inches of total precipitation. On December 27, 2015, 4.96 inches fell in a single day. The worst three-day stretch dropped 8.55 inches, ending December 29, 2015, the kind of soaking that overwhelms sump pumps and storm sewers.
About 71 days a year swing from below freezing at night to above freezing by day. Those freeze-thaw cycles feed ice dams on roofs, open cracks in foundations and driveways, and stress pipes that are already marginal.
Housing
Missouri's 114 counties range widely in housing age; St. Charles ranks 112th, with 25% of its homes built before 1980.
Growth since 2000 added 39% of today's homes. In houses that new, the weak points are washing machine hoses, ice maker lines, water heaters and sump pumps rather than the pipes in the walls.
The 1980s and 1990s account for 36% of the county's homes. If yours is from those decades, look under the sinks and at the water heater for gray plastic pipe stamped PB, which is polybutylene and leak-prone.
Beyond water
About 72 nights a year in St. Charles County stay at 65°F or warmer, a sign of muggy summer air (22nd of 114 counties). July is the wettest month. Mold grows when indoor humidity stays above about 60%, the EPA's ceiling. A basement dehumidifier set to 50% and drying anything wet within 24 to 48 hours prevents most problems.
Mold remediation: what to expectBy main heating fuel, St. Charles County homes break down as 66% utility gas, 30% electric, 3% propane and under 1% wood. Heating equipment, cooking and electrical failures cause most home fires nationally. Even a small kitchen fire can leave soot through the whole house, because smoke follows air currents into closets, ducts and attic space.
Fire and smoke cleanup: first stepsCoverage
Calls connect to restoration companies that work across St. Charles County. The largest communities by population:
Population from ACS 2020-2024 5-year estimates. Townships and unincorporated areas are covered too.
Nearby
Franklin, Lincoln and Warren get more pipe-freeze nights than St. Charles. It also has the most heavy-rain days in its area. St. Louis County has the oldest housing nearby, with 69% of homes built before 1980.
By the numbers
| Factor | St. Charles | Missouri median | Rank |
|---|---|---|---|
| Homes built before 1960 | 6.8% | 25% | 112 of 114 |
| Homes built before 1980 | 25% | 53% | 112 of 114 |
| Homes built 2000 or later | 39% | 21% | 5 of 114 |
| Manufactured or mobile homes | 2.5% | 9.8% | 108 of 114 |
| Vacant homes | 3.5% | 15% | 114 of 114 |
| Wood or propane heat | 3.5% | 25% | 112 of 114 |
| Nights at 20°F or colder | 25/yr | 28/yr | 66 of 114 |
| Days with 1 inch+ of rain | 11/yr | 10/yr | 52 of 114 |
| Freeze-thaw days | 71/yr | 77/yr | 95 of 114 |
| Muggy nights (65°F+) | 72/yr | 65/yr | 22 of 114 |
Rank 1 is the highest value. Bars run from the lowest to the highest Missouri county; the tick marks the median; orange means higher water damage risk than the median, green means lower.
Questions
Peak risk months in St. Charles County: freezing from December to February, heavy rain in April, July and August.
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