Basement mold usually comes from water: seepage through walls, high humidity, condensation or a past leak. Fixing the moisture source matters as much as removing the mold. For areas over about 10 square feet, the EPA suggests an experienced professional.
Why do basements get moldy?
The EPA lists basement walls among common places mold grows indoors. Moisture is the most important factor, and mold doesn’t need much water to grow.
- Groundwater seeping through foundation walls or the floor slab.
- Humid summer air condensing on cool walls, pipes and ducts.
- Leaks from plumbing, water heaters or washing machines.
- Past flooding or sewer backup that wasn’t fully dried.
- Stored cardboard, carpet or drywall that holds moisture.
What should I do first?
- Find and stop any active water: leaks, seepage after rain, a failed sump pump.
- Dry wet items within 24 to 48 hours, as the EPA advises.
- Bring indoor humidity below 60 percent. The EPA suggests 30 to 50 percent as ideal.
- Move stored items off the floor and away from damp walls.
- Don’t disturb large areas of visible mold yourself.
What does basement mold removal involve?
| Step | What happens |
|---|---|
| Moisture check | The company looks for where water enters and how far it spread. |
| Containment | The basement is sealed off so spores don’t reach living areas. |
| Removal | Moldy drywall, carpet, insulation and stored materials are removed. |
| Cleaning | Concrete, block and framing are cleaned and HEPA-vacuumed. |
| Drying | Dehumidifiers and air movers dry the space. |
| Prevention | Waterproofing, drainage, a sump pump or a dehumidifier stops it returning. |
Do I need basement waterproofing too?
If water is getting in, removal alone won’t last. Ask the mold company where the water comes from. A waterproofing or drainage repair may be a separate job, and you can request quotes for it through the same form.
How do I check a mold company in Pennsylvania?
Most home improvement contractors in Pennsylvania must register with the Office of Attorney General. The rule applies to contractors who do $5,000 or more of home improvement work a year.
- The registration number appears as “PA” plus a number on contracts, estimates and ads.
- You can check a registration by calling the Attorney General at 1-888-520-6680.
- Registration is not an endorsement or a quality rating.
- Contracts must be in writing, with the price, start and finish dates, a description of the work and your cancellation rights.
Will insurance cover it?
It depends on your policy and the cause. Many policies limit or exclude mold, and some cover mold that results from a sudden covered water loss. Check the mold and water sections of your policy and ask your agent.
For problems with how an insurer handles a claim, contact the Pennsylvania Insurance Department at 1-877-881-6388.
How getting help works
SEPA Mold Removal is a free referral service, not a mold company. You describe the problem in the form, and independent local mold companies contact you to set up an inspection or a quote.
Questions to ask the company that comes out
- What is your Pennsylvania Home Improvement Contractor (HIC) registration number?
- Which mold certifications does your crew hold, such as IICRC AMRT or ACAC?
- Will I get a written scope covering containment, HEPA filtration and how the moisture source gets fixed?
- Is the inspection or testing done by an independent assessor, separate from the company doing the removal?
- How will you confirm the job is finished? Ask about post-remediation verification or clearance testing.
- Can you send a certificate of insurance and your warranty terms in writing?
Basement mold help by area
Local details by county: Bucks, Montgomery, Chester and Delaware. See all Pennsylvania areas.
Basement mold questions
Mold on basement walls is common, but it means moisture is present. Find and fix the moisture source.
It helps prevent new growth by lowering humidity. It does not remove existing mold.
The EPA recommends indoor humidity below 60 percent, ideally between 30 and 50 percent.
It can if the moisture source isn’t fixed. Ask for a moisture plan in the written scope.
Get matched with a local mold company
Tell us what you’re seeing and where. The service is free. Most property owners hear from a local mold company in 24 hours or less.
SEPA Mold Removal is a free referral service. Your request goes to independent local companies through a partner network. See our Privacy Policy.
Sources
- EPA Mold Course, Chapter 1
- EPA: A Brief Guide to Mold, Moisture and Your Home
- EPA: Mold Cleanup in Your Home
- Pennsylvania Attorney General: Home Improvement Consumer Protection Act
- Pennsylvania Insurance Department: file a complaint
Last reviewed: October 2026