Basement Waterproofing Rules in Missouri: What St. Louis, MO Homeowners Should Know
Drying out a basement in St. Louis, MO involves more than drains and pumps. Local licenses, contract terms, Missouri consumer law and the sewer district all shape the job. Each piece is explained below in plain words, with the office to ask. This is a summary of public law, not legal advice.
The Short Version
If you keep only five points in mind, make them these.
- Licensing happens locally. The City of St. Louis and each County municipality set their own contractor rules.
- Plumbing has its own gatekeepers. Backflow valves, sump lines tied into a drain and lateral repairs belong to a licensed plumber or drainlayer with a permit.
- Get the deal on paper. A signed contract and a payment schedule that follows the work beat any handshake.
- A sale made at your kitchen table can often be undone. You generally have until midnight of the third business day to cancel in writing.
- A backed-up floor drain goes to MSD first. Report it on MSD's 24-hour line, (314) 768-6260.
Verifying a Contractor
Missouri issues no statewide contractor or home improvement license. Inside the City of St. Louis, any contractor performing work or services must carry a graduated business license under City Ordinance 61094, issued by the License Collector at (314) 622-4528. Plumbers and drainlayers hold separate licenses from the City's Boards of Examiners; ask the Building Division, (314) 622-3313.
St. Louis County is a different government with different paperwork. Only master plumbers and drainlayers holding a County license can get plumbing permits there, and many of the County's roughly 90 municipalities add a contractor license or registration of their own. Confirm both layers, and ask for certificates of liability insurance and workers' comp. A push to sign the same day is a reason to keep looking.
As for this site, Basement Waterproofing St. Louis MO only makes free referrals. It is not a contractor and holds no contractor license in the City of St. Louis or in St. Louis County. No basement work, price quotes or contracts ever come from this site. Each request is passed to a single independent local contractor, and that business handles the visit, the estimate and any work you agree to. Contractors may pay the site for advertising, for now as a free trial; you never pay and never receive anything.
Contract Basics
The Missouri Attorney General's office keeps giving homeowners the same advice: collect written estimates, don't pay in full up front, and avoid cash deals. A written contract signed before anyone breaks ground puts that into practice. For a basement job, look for these details.
- Scope and footage. Which walls get a drain, its length in feet, and how the floor is patched.
- Pump specifics. Model, battery backup or alarm, and where the discharge line ends.
- Price and timing. The total, with payments matched to stages of the work.
- Trades and permits. The plumber or drainlayer for anything touching the drain or lateral, and who applies for each permit.
- Warranty language. Coverage, length and whether it transfers to a buyer.
Missouri's Merchandising Practices Act (RSMo 407.020) makes it unlawful to use deception, false promises or misrepresentation, or to leave out an important fact, in connection with a sale or its advertising. It reaches sales talk and ads alike, this site's included, which is why every statement here is kept literal. If a business misled you, the Attorney General's Consumer Protection hotline is 800-392-8222.
The Three-Day Cancel Rule
When a contractor sells you a job at your own home, Missouri law and federal rules generally let you cancel until midnight of the third business day after you sign. Saturdays, Sundays and holidays don't count. Mail a written cancellation to the address on the contract and keep proof of mailing; under the Missouri statute, it counts once sent. Deals signed at the company's office, or emergency work you requested, may fall outside the rule.
Missouri also makes it a crime to financially exploit an older adult or a person with a disability (RSMo 570.145), including taking money by deceit or by promising work that was never meant to happen. If an older relative feels rushed toward a big contract, read it through together first.
Help for Sewer Backups
MSD, the Metropolitan St. Louis Sewer District, handles sewers for the City and nearly every part of St. Louis County. In the City and the older inner suburbs, rainwater and wastewater share combined sewers, many of them old brick tunnels; much of the County has separate lines. When a storm overloads a combined pipe, the mix can rise through a floor drain. That is a sewer backup, not seepage, and waterproofing won't stop it.
Report any backup on MSD's 24-hour line, (314) 768-6260. When MSD's system is at fault, MSD may repay part of the loss, capped at $3,000 with a $100 deductible when heavy rain overloaded the sewer, provided you contact MSD within 30 days. Private lateral trouble and water entering through foundation cracks aren't covered.
Customers with a history of backups traced to MSD's system may qualify for its Sewer Backup Prevention Program, which can pay for a backflow device or check valve through MSD's Customer Care Center; private plumbers hired outside that process aren't repaid. In certain project areas, MSD crews unhook downspouts and sump discharge lines from the wastewater system, and the owner pays nothing for it.
The lateral, meaning the pipe from your house to the sewer main, is yours to maintain. In the City, a $28 yearly charge on the tax bill funds the Sewer Lateral Repair Program, which pays for breaks beneath the public right-of-way at buildings of up to six units. County cities run their own versions. This site has no role in any of these programs.
On insurance, standard homeowners policies often lack sewer backup coverage unless an endorsement was bought for it, and seepage is a common exclusion, so read your own policy and take questions to your insurer or agent.
Checking Permits First
Inside the City, plumbing permits go to City-licensed plumbers and cover jobs such as a new sewer lateral, while building permits apply to foundation or footing repair, underpinning and shoring; tuckpointing is generally exempt. For drain tile or a sump alone, it depends on the scope, and checking with the Building Division is the contractor's job. County cities add their own steps.
- University City, MO. Only County-licensed master plumbers or drainlayers get plumbing permits; homeowner permits exclude laterals and building drains. Planning & Zoning: 314-505-8500.
- Webster Groves, MO. Contractors register with the city, and only those on its list get permits, apart from owners working on their own home. City Hall: 314-963-5300.
- Kirkwood, MO. Contractors need a Kirkwood Contractor's Business License; permits cover plumbing and sewer lateral work. Building Division: 314-822-5823.
- Florissant, MO. Plumbing and basement remodeling need permits, and subcontractors list their license numbers on them. Building Division: (314) 839-7648.
- Chesterfield, MO. The city grants a zoning approval first, and then St. Louis County issues the permit. County permits: 314-615-5184.
Rules shift, so check with the office for your address before digging starts.
Questions About the Rules
Does Missouri license basement waterproofing companies?
Not at the state level. In the City of St. Louis, a contractor needs a City business license from the License Collector, (314) 622-4528, and plumbing or drainlayer work needs a City trade license. In the County, check the County plumbing license and your municipality's own rules.
Will MSD pay for a backflow valve?
Possibly, if your backups trace back to MSD's system. Its Sewer Backup Prevention Program may cover a backflow device or check valve for customers with that history, arranged through MSD itself rather than a plumber you hire. Start with the 24-hour line, (314) 768-6260.
Source List
All read 2026-10-10. Statutes and program details get updated, so confirm the latest text.
- RSMo 407.020. Deception in sales and advertising.
- RSMo 407.700–407.720. Cancel rights for sales made at the buyer's home.
- RSMo 325.010–325.015. Adjusting losses for policyholders.
- RSMo 570.145. Financial exploitation of older adults.
- stlouis-mo.gov. City pages for the License Collector, the Building Division and lateral repairs.
- msdprojectclear.org. Combined sewers, backups and MSD programs.
- City websites. ucitymo.org, webstergrovesmo.gov, kirkwoodmo.org, florissantmo.com and chesterfield.mo.us.
Get a Written Estimate
With the rules sorted out, the useful next step is a written price for your own basement. Fill out the short request form, and one independent local contractor in the St. Louis area will reach out, look over the walls and floor, and put scope and cost in writing. Ask to see its license at that visit. For a ballpark first, try the cost calculator or the wet basement checker.