Basement Waterproofing in St. Louis, MO
A wet basement in St. Louis, MO usually has a cause someone can find, whether it's a downspout emptying beside the wall, worn mortar in an old brick foundation or a sewer pushing back in a cloudburst. Fill in the short form and a single independent local contractor receives it, visits and puts a price on paper. The referral is free, and this site does no basement work.
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Basement Estimate Request
Takes about 30 seconds. One local contractor gets it and contacts you.
Your details go to one independent contractor who works around St. Louis, MO, and that contractor gets in touch with you directly. See our Referral Marketing Disclosure.
Wet Basement in St. Louis? Start With the Facts
St. Louis houses tend to be old: the typical City home was built around 1938, and about 58% date from 1939 or earlier (Census survey). Water can slip in where brick or limestone mortar has gone soft, along the joint at the base of the wall, through a window well or up a floor drain. Sorting out which takes someone standing in your basement, which is why each request ends with a contractor coming out and writing an estimate.
Basement Waterproofing St. Louis MO only passes requests along. It holds no City of St. Louis or St. Louis County contractor license, never offers or performs basement work, sets no prices, signs no contracts and keeps out of insurance questions. Contractors may pay this site to advertise, currently on a free trial; homeowners are never charged and are given nothing for asking.
How It Works
- Tell us about the water. Use the short form to share your address and where the damp shows up.
- It reaches one company. A single independent contractor working around St. Louis gets your request, and no other firm sees it.
- They come out and look. Walls, floor, drains, gutters and the slope of the yard all get checked, and you hear what seems to be happening.
- You decide with the numbers in front of you. Read the written estimate, confirm the license with the City or your municipality, and take your time.
Basement Services in St. Louis
Basement Red Flags to Watch
- Wet edges along the floor. Damp where the wall meets the slab after rain often means water is pressing in from outside the footing.
- A chalky white crust on brick or stone. Minerals stay behind as water dries; crumbling mortar in an older foundation deserves watching too.
- A crack that turns dark in storms. If it gets wet, water is getting through. Have a horizontal crack, or a wall bowing inward, looked at soon.
- A sump that cycles without a break. Nonstop running, or a pump that has quit, may mean it is facing more water than it was sized for.
- Water rising through a floor drain. That usually signals a sewer backup rather than seepage; the rain and snowmelt section below says who to contact.
A Quick Wet-Basement Self-Check
Five quick questions in the wet-basement checker point to one of three next steps. It diagnoses nothing, but it helps you describe the problem.
Rain, Snowmelt and St. Louis Basements
Spring storms, summer downpours and freeze-thaw can all test a basement here. On July 26, 2022, Lambert airport logged 8.64 inches, its wettest day on record, and the National Weather Service issued the area's first flash flood emergencies. April 2025 then became the wettest April on record in St. Louis, at more than 10 inches (St. Louis Public Radio). Much of the region sits on loess and clay over limestone, and clay can hold water against a wall (U.S. Geological Survey).
Water coming up a floor drain is a sewer matter. The City and older inner suburbs have combined sewers, carrying rain and wastewater in the same pipes, so a big storm can push both back. Report a backup to the Metropolitan St. Louis Sewer District's 24-hour line at (314) 768-6260. If MSD's system caused it, MSD may reimburse some losses, and its Sewer Backup Prevention Program may pay for a backflow device for customers with a history of MSD-caused backups. The lateral to the main is the owner's.
Budgeting for a Dry Basement
These are Fixr's 2026 national numbers, not a St. Louis price list.
| Cost row | Figure | Source (year) |
|---|---|---|
| Typical basement waterproofing project | about $3,000 to $10,000 (average about $5,000) | Fixr national (2026) |
| Interior perimeter drain, per linear foot | $40 to $120 | Fixr national (2026) |
| Sump pump installation | $600 to $2,500 | Fixr national (2026) |
| Epoxy crack injection, per crack | $250 to $1,000 | Fixr national (2026) |
| Waterproof paint or sealant, per sq ft | $1 to $8 | Fixr national (2026) |
Backflow valves are left out, because MSD's program may cover one when its sewers caused the trouble. The cost guide covers what moves a total, and the calculator below sketches a range for your basement.
A Simpler Way to Get an Estimate
- Tell the story once. One company hears it, so you aren't repeating yourself to several salespeople.
- A written scope you can compare. Ask for the drain length, pump model, discharge point and warranty terms on paper.
- The checking is yours. This site vouches for no one, so confirm the City business license, or your municipality's, yourself.
Nearby Towns We Connect
Requests come from North City, South City and across St. Louis County. Five County cities have their own pages: University City, MO to the west, Webster Groves, MO to the southwest, Kirkwood, MO a bit farther out, Florissant, MO in North County and Chesterfield, MO in West County.
St. Louis Homes and Their Basements
St. Louis has about 278,000 residents (2025 Census estimate). Brick became the rule after the fire of 1849, and the City is still lined with two-family and four-family brick flats, where several units often share one basement, so a drain or pump decision touches every household.
Common Questions
Does anyone from this site come to my house?
No. Once your request reaches the contractor, this site's part is finished. Nobody from here visits, measures or prices anything; the visit, the estimate and any work you agree to sit with that independent company.
My floor drain backed up. Is that a waterproofing job?
Probably not; that usually points to a sewer backup rather than groundwater. Report it to MSD's 24-hour line at (314) 768-6260 and ask whether its Sewer Backup Prevention Program applies. For a lateral broken under the street, the City's Sewer Lateral Repair Program, or your County city's own program, may help.
Will homeowners insurance pay for a wet basement?
Policies differ. Many leave out sewer backups unless a separate endorsement was added, and slow seepage is commonly excluded. Read yours and ask your insurer or agent before work begins; this site plays no part in insurance.
How do I check a contractor in St. Louis?
Missouri has no statewide contractor license, so checking is local. City contractors need a business license from the License Collector, (314) 622-4528, and the Building Division, (314) 622-3313, answers questions about plumbers and drainlayers. In St. Louis County, ask your municipality what it requires, and make sure plumbing goes to a County-licensed master plumber or drainlayer.
Talk to a Local Contractor
Send the short form whenever it suits you. One independent contractor will reach out to set up a visit, and what happens after the estimate is your decision alone.