Basement Waterproofing Rules in Maryland: What Baltimore, MD Homeowners Should Know
A basement project in Baltimore, Maryland runs into state licensing law, contract and payment rules, a plumbing statute, and a permit office that depends on your side of the city line. Each rule names the office that can confirm it. This is a summary of public law, not legal advice.
The Short Version
- One state license covers the trade. There is no separate waterproofing license; the Maryland Home Improvement Commission (MHIC) licenses home improvement work.
- No money before the signature. Nothing is owed until you sign, and the deposit can't top one-third of the price.
- A sale at home has a short exit. A deal struck in your house can generally be undone until midnight of the third business day.
- Pipes belong to a plumber. Sump tie-ins, backwater valves and laterals are work for a Maryland-licensed plumber.
Checking a Contractor's License
The Maryland Home Improvement Law (Business Regulation Article, Title 8) makes anyone who performs a home improvement, or offers or agrees to, a contractor, and a wet-basement fix is a home repair. Contractors and the salespeople selling their work each need an MHIC license; working or selling without one is a misdemeanor, with up to $1,000 and six months in jail for a first offense. Neither Baltimore City nor Baltimore County may add a local license, though both issue permits.
Use MHIC's online license lookup at labor.maryland.gov/license/mhic, or reach the Commission at 410-230-6231 or 1-888-218-5925. A contractor's ads must show its name and MHIC number, can't mislead, and must state the terms and length of any warranty. Offering an owner a gift, bonus or cash to win a contract is off limits, though a sale price doesn't count.
The license also opens a safety net: when a contractor holding one causes an eligible homeowner an actual loss, the state's Home Improvement Guaranty Fund can repay up to $30,000 per claimant for that contractor. Unlicensed work is outside the Fund. The contractor's relatives and staff are excluded, as are owners of more than three homes who don't live in the one at issue, and no recovery is assured.
Maryland's plumbing law (Business Occupations Article, Title 12) reserves piping for sanitary and storm drainage to plumbers licensed by the Maryland State Board of Plumbing (410-230-6379). An owner's right to work on their own home stops short of hooking it to an outside sewer.
Those rules shape this site. Basement Waterproofing Baltimore MD advertises and passes along requests; it holds no MHIC license, is neither a home improvement contractor nor a salesperson, offers no basement work, seeks no contract for anyone and names no contractor. One independent contractor receives your request, gets in touch and writes its own estimate, and may pay this site a flat advertising fee, waived during a trial for now. Homeowners are never charged or given anything.
Written Contracts and Estimates
Under §8-501, the contract must be written, legible and signed by everyone. Before signing, check for:
- Who you are dealing with. The contractor's name, address, contact number and MHIC number, plus any salesperson's name and license number.
- MHIC's notice. The Commission's number and website, and a line saying every contractor needs its license.
- A rescission line if the house secures payment. Page one must say you may rescind within 3 business days of signing, with your initials.
- Payment inside the limits. Nothing before signing, and no more than one-third of the price as a deposit.
- A measurable scope. Which walls, feet of drain, the pump, its discharge point, who pulls each permit, and written warranty terms.
Cooling-Off Rules
Maryland's Door-to-Door Sales Act generally covers a sale of $25 or more agreed anywhere but the seller's place of business, your living room included, even when you invited the contractor in. You should receive written notice that you may back out until midnight of the third business day afterward, plus a cancellation form. If that notice is missing, you can generally cancel by any means.
The Maryland Consumer Protection Act outlaws deception, such as claiming a connection a business lacks, hiding a material fact or wrongly saying a repair is needed. For complaints or a company's complaint history, contact the Attorney General's Consumer Protection Division, (410) 576-6557.
What the City Covers
This section is about Baltimore City addresses, not Baltimore County. Under a 2002 federal consent decree, modified in 2017, the City split its combined sewers into separate storm and sanitary pipes, so City backups come from the sanitary line surcharging.
DPW leaves the lateral and its cleanout on the owner's side of the property line to the owner. City Code keeps groundwater and subsurface drainage out of the sanitary sewer without a DPW permit, so a sump must never empty there. Report a backup to 311, or (443) 263-2220 from outside the City.
DPW's Expedited Reimbursement Program is open to City residential owners and tenants whose backup followed a capacity-related wet-weather event, defined as a quarter inch or more of rain in 24 hours. Documented cleanup, disinfection and disposal costs are repaid up to $5,000 per dwelling unit, per event; property damage is not. Apply within 90 days; backups before April 6, 2018 don't count, and the City has owners with insurance wait for their insurer's final decision. Questions: 410-396-3500.
SOS (Sewage Onsite Support) Cleanup sends City-contracted crews, free, to clean, disinfect and dry a basement after a City-confirmed wet-weather backup, though not for clogs, roots or grease. It is a pilot, so ask 311 whether it is running. You may use SOS or the reimbursement program, not both. Property damage is a separate claim with the City Law Department, 410-396-3400, and filing doesn't promise payment.
None of this runs through this site or any contractor. Policies often need a separate endorsement for sewer backups and commonly exclude seepage; your policy, insurer or agent has the answer. In the County, sewer emergencies go to DPWT's Emergency Sewer Service, 410-887-7415, and the City's programs don't apply.
Permit Questions
Baltimore City permits come from DHCD. Significant alterations, grading and excavating need one, and the City's no-permit list leaves out waterproofing, sump pumps, foundations, excavation and retaining walls. One- and two-family home work requires a contractor holding an MHIC license, and plumbing a licensed plumber. Permits Office: 443-984-1809, or online through E-Permits.
Underpinning in the City, which lowers a floor below a wall, adds sealed drawings by a Maryland-licensed architect or engineer, a pre-permit meeting and inspections; on a rowhouse party wall, adjoining owners get written notice at least 10 days before filing.
Baltimore County's Permits, Approvals and Inspections (PAI) requires permits, with the contractor's MHIC number, for alterations and structural work on existing homes, and only a Baltimore County licensed plumbing contractor may apply for a plumbing permit. PAI is at 111 West Chesapeake Avenue, Room 100, Towson: 410-887-3900.
Either way, structural, excavation and foundation repairs usually need a building permit with the contractor's MHIC number, plumbing needs a plumber's own permit, and the contractor confirms which apply.
Answers on Permits and Contracts
Does interior drain tile need a permit on its own?
Ask the office for your address: DHCD at 443-984-1809 in Baltimore City, or PAI at 410-887-3900 in Baltimore County. Tying that drain into any pipe is plumbing, with a permit pulled by a Maryland-licensed plumber.
How much can a contractor ask for before work starts?
Nothing until the contract is signed, and then no more than one-third of the price as a deposit, whatever the size of the job. A request for more up front is a reason to pause and ask questions.
What should I do when water comes up through a floor drain?
Treat it as a likely sewer backup, not seepage: City homes report it to 311, County homes to DPWT at 410-887-7415. A backwater valve or sewer repair is work for a Maryland-licensed plumber with a permit.
Where to Check
All read 2026-10-10; confirm current versions with each office.
- Business Regulation §§8-101, 8-102 and 8-301 (licensing), 8-405 (the Fund), 8-501, 8-503 and 8-504 (contracts, gifts, permits), 8-601 and 8-617 (penalties, deposits). On mgaleg.maryland.gov.
- COMAR 09.08.01.02 and 09.08.01.09, plus 09.08.06.02; labor.maryland.gov. MHIC rules, the license lookup and the Board of Plumbing.
- Commercial Law §13-301 and §§14-301 to 14-303; Insurance §10-401; Business Occupations §§12-101 and 12-301. On mgaleg.maryland.gov.
- Baltimore City Code Art. 25 §2-3; publicworks.baltimorecity.gov. The groundwater rule, both City programs, the consent decree and DPW's backup guide.
- baltimorecity.gov and baltimorecountymd.gov. DHCD permits and the underpinning guideline; PAI permits and DPWT utilities.
Start With One Request
Rules tell you what to ask; a written estimate tells you what your job involves. Send the short request form and it goes to one independent contractor serving the Baltimore area, who reaches out, looks over the walls and writes up a scope and price. For a ballpark first, open the cost calculator or the wet basement checker.