Leak guide › Mold after a leak
A small patch on a dry wall: you can clean this yourself
The EPA says a patch under about 10 square feet is in most cases a homeowner job, as long as the moisture source is already fixed.
What is probably happening
- Surface growth on paint or paper facing from a past leak, condensation or a humid room.
- If the wall is dry and the leak is fixed, the growth has stopped. Cleaning removes what is left.
- If the drywall is soft, crumbly or stained through, the mold is probably inside it and the panel needs cutting out, not scrubbing.
Do this in the next five minutes
- Confirm the source is fixed: no drip, no damp, no condensation. If not, go back and pick 'still wet'.
- Put on an N95 respirator, goggles and rubber or nitrile gloves. Open a window.
- Scrub hard, non porous surfaces with detergent and water. Dry completely.
- Throw out moldy porous items such as ceiling tiles, carpet padding and cardboard. Bag them before carrying them through the house.
- Photograph the patch before and after, in case it comes back.
Do not
- Do not reach for bleach first. The EPA does not recommend bleach or other biocides as a routine practice, and dead mold still causes allergic reactions, so it has to be removed, not just killed.
- Never mix bleach with ammonia or any other cleaner. The fumes are toxic.
- Do not just paint over it. Paint over mold peels, and the growth continues underneath.
- Do not pay for an air test. The EPA says that when you can see mold, sampling is unnecessary.
Who to call
Usually nobody. A mold remediation contractor if it comes back
Under about 10 square feet on a dry surface is inside the EPA's do it yourself range. A contractor earns their fee when the area is larger, hidden, or the source is unknown.
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What it should cost
Usually no contractor cost
EPA: under about 10 square feet, in most cases you can handle the job yourself. If you hire out anyway, Angi puts bathroom sized jobs at $500 to $1,000
Source: US EPA brief guide and Angi, mold remediation cost, July 2026. View source
National published range, not a quote for your job. The full cost table for this trade is on the mold after a leak page.
Ask this contractor, on the phone, before anyone comes out
Tap each one as you ask it.
- If I call you for a patch this small, is there a minimum charge, and what is it?
- What is the moisture source, and is finding it part of your visit?
- Will you remove the material or just treat it, and why?
End the call if
- A quote that starts with an air test for a patch you can see and measure.
- A whole house fogging or 'treatment' sold for a 2 foot patch.
- Anyone who says the patch must be identified by species before it can be cleaned. CDC: you do not need to know the type of mold.