How to remove mold from carpets, and when to throw them out

Step by step: how to remove mold from carpets, and when to throw them out

Safety first. Mold can trigger allergies and asthma. Wear an N-95 respirator, goggles without vents and long gloves, and keep children, pets and anyone with asthma or a weak immune system out of the room. Do not use bleach on carpet, and never mix bleach with ammonia or other cleaners. Keep electrical cords and fans away from wet carpet.

1. 1

   Find and stop the water source

   Mold in carpet always means moisture: a leak, a flood, a spill that never dried, a damp slab or high humidity. Fix the leak or drainage problem before you clean, or the mold will be back within weeks. Check the underside of the carpet and pad, since mold often starts there.

2. 2

   Judge whether it can be saved

   Lift a corner and look at the back and the pad. If mold covers more than about 10 square feet, the carpet was soaked by sewage or floodwater, or the pad is black and smells, plan to remove it. A few small spots on the surface of carpet that got wet once can usually be cleaned.

3. 3

   Dry the area completely

   Run a dehumidifier and point box fans across the carpet, and open windows if the air outside is dry. If you can, lift the carpet and blow air underneath it. Aim to get everything dry within 24 to 48 hours.

4. 4

   Vacuum the surface with a HEPA vacuum

   Put on your respirator, goggles and gloves. Vacuum the moldy area slowly with a HEPA-filter vacuum to pull spores out of the pile. Empty the canister or bag outside into a sealed plastic bag.

5. 5

   Treat the back with diluted hydrogen peroxide

   For a rug or a lifted section of carpet, mix 1 part 3 percent hydrogen peroxide with 5 parts water and brush it onto the back where the mold is. Test it on a hidden area first, since peroxide can lighten dyes. Small rugs can go outside in direct sun for a day or two to help.

6. 6

   Wash the face with detergent suds

   Whip a few squirts of dish soap into a bowl of water until you have thick suds. Sponge just the suds onto the surface, which cleans without soaking the backing, then wipe with a cloth dampened in clean water. Blot well.

7. 7

   Dry it fast and check again

   Run fans and the dehumidifier until the carpet and pad are fully dry, usually 1 to 2 days. Check the spot and smell it again a week later. A musty smell or new spots mean mold is still in the pad or subfloor.

Can moldy carpet be cleaned, or does it need replacing?

Small surface mold on carpet that got wet once can usually be cleaned; carpet with widespread mold, soaked padding or floodwater contamination usually cannot. Carpet is porous, so mold grows down into the fibers and backing where you cannot reach it.

The EPA’s mold cleanup guidance says absorbent or porous materials such as carpet may have to be thrown away if they become moldy, because mold can fill the spaces in those materials and be difficult or impossible to remove completely. The EPA also says you can generally handle a moldy area smaller than about 10 square feet (roughly 3 feet by 3 feet) yourself; for larger areas or a lot of water damage, consult a professional.

Should you use bleach or vinegar on moldy carpet?

Do not use bleach on carpet. It strips the color, weakens fibers and can damage the backing, and it does not reach mold growing underneath.

Shaw’s carpet care guide says bleach cannot be used as a carpet cleaner and can cause the backing to delaminate, and lists mildew removers among household products that can discolor or dissolve carpet fibers. The EPA adds that killing mold with a biocide such as chlorine bleach is not recommended as routine practice, because dead mold can still cause allergic reactions and has to be removed, not just killed. The University of Georgia Extension instead suggests drying, sunlight, a diluted hydrogen peroxide solution on the back of the carpet, and washing with suds. White vinegar is often suggested online; it is mild on synthetic carpet, but it does not fix the moisture that let mold grow.

How to keep mold from coming back in carpet

Keep carpet dry and indoor humidity low. Mold cannot grow without moisture, so prevention is mostly about water.

• Dry wet carpet within 24 to 48 hours. The EPA says that if wet materials are dried in that window, in most cases mold will not grow.
• Keep indoor humidity below 60 percent, ideally 30 to 50 percent. A cheap hygrometer tells you where you stand.
• Avoid wall-to-wall carpet in basements, bathrooms and other rooms that get damp. Use washable area rugs there instead.
• When you shampoo carpet, extract as much water as possible and run fans afterward so it dries in hours, not days.

A musty smell without visible mold is covered in how to get mildew smell out of carpet, and damp below-grade rooms in how to get rid of mold in a basement.

Mistakes to avoid

• Cleaning the mold without fixing the leak or humidity that caused it.
• Pouring bleach on carpet, which discolors it and leaves mold in the backing.
• Shampooing moldy carpet with a wet machine and then letting it dry slowly.
• Vacuuming moldy carpet with a non-HEPA vacuum, which blows spores back into the room.
• Saving carpet that was soaked by floodwater or sewage.
• Working without a respirator in a closed room.