How Fast Does Mold Grow After a Leak? 24 to 48 Hours

Mold spores are everywhere, indoors and out. They float in the air and land on every surface. Most of the time they do nothing. They start to grow when they get four things:

1. Moisture, from a leak, flood or high humidity.
2. Food, like the paper on drywall, wood, dust and fabric.
3. Mild temperatures, the same ones people like.
4. Time.

You cannot remove the spores, the food or the comfortable temperature from a home. The one thing you can control is moisture. That is why fast drying matters so much.

Note: this is a general timeline, not an exact clock. Warm, dark, dusty spaces can grow mold faster. Clean, cool, well-dried spaces may never grow it at all.

• Back of drywall and the bottom few inches of walls.
• Carpet pad, especially over concrete.
• Under sinks and inside cabinets with particle board.
• Behind baseboards and under vinyl or laminate floors.
• Crawl spaces and attics, where nobody looks. See why crawl spaces get wet.
• Ceilings below bathrooms and roof leaks.

• Slow, hidden leaks that keep materials wet for weeks. Read signs of a hidden leak.
• Dirty water from toilets, sewers or floods, which carries extra food for mold. See clean, gray and black water.
• High indoor humidity. Keeping humidity below about 60 percent helps, and lower is better.
• Poor air flow in closets, behind furniture and in closed rooms.
• Our damp winters. In Western Washington, cool, wet air slows natural drying, so wet materials stay wet longer.

The EPA suggests that a homeowner can usually clean a mold area smaller than about 10 square feet, about a 3 foot by 3 foot patch, on hard surfaces, as long as the water problem is fixed.

If you clean it yourself

• Wear gloves, eye protection and an N-95 mask.
• Scrub hard surfaces with water and detergent, then dry them fully.
• Throw away porous items like ceiling tiles or carpet pad that stay moldy.
• Do not paint over mold. It will grow back.

Call a professional when

• The area is larger than about 10 square feet.
• Mold is inside walls, in HVAC ducts, or under floors.
• It came from sewage or flood water.
• Someone in the home has asthma, allergies or a weak immune system.

These steps work for small spills and big leaks alike. The goal is simple: get everything dry, fast.

1. Stop the water and remove standing water the same day.
2. Pull up wet rugs and pad and move them somewhere they can dry, or throw them out.
3. Run a dehumidifier with the room closed, and empty it often.
4. Move air with fans aimed at wet walls and floors.
5. Open cabinet doors and drawers, and pull furniture away from walls.
6. Check again in two days. If anything still feels damp, cool or smells musty, get it measured.

Mold and your health

According to the CDC, mold can cause stuffy noses, coughing, wheezing, and itchy eyes or skin in some people. People with asthma, allergies or weak immune systems can react more strongly. If anyone in your home feels sick, talk to a doctor, and fix the moisture problem as soon as you can.

1. Find and fix the moisture with meters and thermal cameras.
2. Contain the area with plastic walls and air pressure control so spores stay put.
3. Remove what cannot be cleaned, like moldy drywall and pad.
4. Clean and HEPA vacuum the remaining surfaces.
5. Dry everything to normal levels before rebuilding.

Not sure if you have mold? Our mold inspection and testing can tell you. We serve Kirkland, Finn Hill, Kingsgate, Woodinville and more.