Quick answer
For water damage in Clarkson Valley, MO, shut off your main valve first, or turn off the well pump breaker if you are on a private well. Heavy rain can fill the sewer lines, so report basement sewage to MSD quickly. Then call a water damage restoration company; drying should start within 24 to 48 hours. Missouri insurers must acknowledge your claim within 10 working days.
Do this first
Local water and sewer lines.
Missouri American Water, MSD sewer lines, and the St. Louis County flash flood table are on the Maplewood page.
- Shut off the water. Shut the house valve first. A leak in the street or yard is a Missouri American Water job; the Maplewood page has its emergency number.
- Make it safe and document it. Cut power to wet rooms from a dry spot, photograph the damage, then report the claim.
- Start drying within 24 to 48 hours. When a storm floods the sanitary lines and a basement drain overflows, call the sewer district right away and ask whether a backwater valve is offered for your home.
In July and August 2019, torrential rain filled the sanitary sewers serving this part of west county and pushed sewage into basements more than once.
What to know about water damage in Clarkson Valley
0.9 mi
Distance from Clarkson Valley to the Spirit of St. Louis Airport weather station, which averages 105 nights a year at or below freezing.
Sewage in basements
In August 2019, KSDK reported Clarkson Valley and Ballwin families with sewage in their basements again after heavy rain filled the sewer lines. MSD planned a project to remove storm water from the sanitary sewers along Clarkson and Kehrs Mill roads.
Source: KSDK
Village to city
Clarkson Valley started as a village in 1950 and became a fourth-class city in 1989.
Homes in Clarkson Valley
The median home dates to 1982 and about 97% are owner-occupied. Only about 1% were built before 1960.
How often it freezes
The NOAA weather station at Spirit of St. Louis Airport averages 104.7 nights a year at or below 32°F and 33.0 at or below 20°F. In half of years the first freeze comes by October 23 and the last one after April 12. Pipes in outside walls, unheated basements, and crawlspaces are the first to split.
Check your ZIP
Flash flood warnings in St. Louis County
The National Weather Service issued 58 flash flood warnings that included St. Louis County from 2016 through November 12, 2026. The year-by-year count is on the Maplewood page.
Cost and insurance in Clarkson Valley
How much does water damage restoration cost in Clarkson Valley?
Most jobs run $450 to $16,000 (Angi). Storm water that enters from outside is a flood claim. Finished basements with carpet and built-ins can take a week or more.
Water removal and restoration in Clarkson Valley
The company that answers handles basement sewer backups, sump pump failures, burst pipes, water heater failures, and leaks in finished basements, plus burst pipes, appliance leaks, drying, and septic backups.
Clarkson Valley questions
What did MSD offer families after the 2019 backups?
KSDK reported that MSD offered one family a free sewer backup valve and $3,000 for homes hit by sewer overcharges.
Why do Clarkson Valley basements get sewage after storms?
MSD told KSDK that heavy rain filled the sewer lines. A sewer backup endorsement on your policy matters here.
Who can answer city questions in Clarkson Valley?
City Hall, at 636-227-1914, open business hours.
Is Clarkson Valley part of Chesterfield?
No. It has been its own city since 1989, but it shares ZIP 63005 with Chesterfield, which makes up most of that ZIP.
Related guides
Other Missouri towns- Burst pipe, not frozen
- Water mitigation vs. restoration
- Burst pipe repair cost
- Missouri insurance claim rules, in plain English
- Frozen and burst pipes: what to do
- Does homeowners insurance cover water damage?
- How long water damage takes to dry
Local phone numbers checked November 2026: