Found mold from a water leak? Dry things first, then decide who cleans it.

A dark patch after a leak does not wait for a plan. The order still matters. Find the moisture first, then decide what you can clean and what needs a crew.

Stop the water if you can reach the valve dry

Mold needs moisture. The EPA mold guide says the key to mold control is moisture control, and that if you clean the mold but leave the water problem, the growth usually comes back.

If a supply line, a water heater, or a running toilet is still feeding the room, turn the shutoff from a dry path. If you cannot reach it without wading, leave it and get help. Standing in water to reach a valve is not worth a fall or a shock.

Watch the 24 to 48 hour window

The EPA says it is important to dry water-damaged areas and items within 24 to 48 hours to prevent mold growth. In another line on the same page, it says that if wet or damp materials are dried 24 to 48 hours after a leak or spill, in most cases mold will not grow.

The CDC is stricter once outdoor water has been in the house. Its respiratory cleanup page says that if the home was flooded and you could not completely dry it out, including furniture and rugs, within 24 to 48 hours, you probably have mold. How soon does mold grow after a leak? is the short version.

Clean a small patch yourself if the leak is already fixed

The EPA cleanup page says that if the moldy area is less than about 10 square feet, less than roughly a 3 foot by 3 foot patch, in most cases you can handle the job yourself. Can I clean a small mold patch myself? walks through that limit.

That is a size limit, not a health promise. The EPA also says that in most cases, if visible mold growth is present, sampling is unnecessary. Do I need a mold test before cleanup? covers when a sample still helps.

Keep indoor humidity below 60 percent, and ideally between 30 and 50 percent, once the room is dry. The EPA says a small humidity meter from a hardware store is enough to check that.

Treat flood water and sewage as a different job

The CDC cleanup page says to throw away porous items that stayed wet with flood water and cannot be cleaned, including mattresses, carpeting, carpet padding, and upholstered furniture. It also says to remove and discard drywall and insulation contaminated with sewage or floodwater.

Clean supply water on a small tile patch is a different job from outdoor water in a basement. A crew should tell you which one they think they are looking at before they start tearing out walls.

Call your insurer if a sudden leak started it

The Texas Department of Insurance says most homeowner policies cover sudden accidental water, such as a burst pipe, and that if mold develops on a damaged item from that event it would be covered. Gradual leaks and flood mold are usually left out. Does homeowners insurance cover mold? keeps those apart.

Photograph the room before you move furniture. A company you hire cannot decide coverage.

When a company starts to make sense

Spores are already in house dust. They need moisture to grow. A crew starts to make sense when the patch is larger than about 10 square feet, the water was sewage or outdoor flood water, the wall stayed wet through a weekend, or you cannot find the leak. Large jobs often start with containment so the work stays in one room. How to choose a mold inspection or cleanup company is the checklist for that call.

Questions people ask next

• How soon does mold grow after a leak?
• Does homeowners insurance cover mold?
• Can I clean a small mold patch myself?
• Do I need a mold test before cleanup?

If you are in a humid Gulf or river city, the local permit and license rules change what to ask first. Start with Lake Charles, Beaumont, Wilmington, or Tuscaloosa.