"Black mold" usually means Stachybotrys chartarum, a greenish-black mold that grows on materials like drywall, fiberboard and paper when they stay wet. But plenty of other molds look dark too, and color doesn't tell you how risky a mold is. The CDC says all molds should be treated the same when it comes to health risks and removal: find the moisture, remove the growth, and keep the area dry. Small patches on hard surfaces you can often clean yourself. Larger areas, mold inside walls, or mold after a leak or flood are jobs for a specialist. This page covers what to do first, what removal involves, and what it costs.
What should I do if I find black mold in my house?
If you find black mold, start by finding the water that feeds it: a leak, condensation, or a damp area that never dries. Fix that first. Then measure the patch. The EPA says most people can clean an area under about 10 square feet themselves. For anything bigger, or mold on drywall or after water damage, get a specialist to look.
Steps that help in the first few days:
- Don't disturb it more than you need to. Scraping or sanding dry mold puts spores into the air.
- Find the water. Look above and around the patch for leaks, sweating pipes or a wet wall. Mold on drywall almost always means the drywall has been wet for a while.
- Keep people with asthma, allergies or weak immune systems away from the area.
- Photograph it before anything is cleaned, in case you make an insurance claim.
- Decide: clean it or call someone. Use the 10 square foot rule, and our guide on how to get rid of black mold safely if the patch is small.
Is black mold more dangerous than other mold?
The CDC says all molds should be treated the same with respect to potential health risks and removal, and that you don't need to know the type of mold before you clean it up. Any mold growing indoors can cause symptoms in some people. The color of a mold doesn't tell you how harmful it is.
Stachybotrys can produce mycotoxins in some conditions, which is where the "toxic black mold" reputation comes from. But the CDC notes that a link between Stachybotrys and serious lung bleeding in infants, the cases that made it famous in the 1990s, has not been proven, and that no test can show a link between this mold and particular symptoms.
What the CDC does say about damp, moldy homes in general:
- they can cause a stuffy nose, sore throat, coughing or wheezing, burning eyes, or a skin rash in some people
- people with asthma or mold allergies may have stronger reactions
- people with weak immune systems or chronic lung disease are at higher risk of infection
- anyone with symptoms that don't go away should see a doctor
Is it black mold, mildew or Cladosporium?
You usually can't tell black mold from other dark molds by looking. Mildew is a loose name for mold that grows flat on surfaces, often gray or white, and wipes off easily. Cladosporium, one of the most common indoor molds, is often dark green or black too. Stachybotrys looks slimy when wet and grows where material stays soaked.
A rough guide to what people find:
| What you see | Often | Where |
|---|---|---|
| Gray or black spots that wipe off | Mildew or surface mold | Shower grout, window sills, bathroom ceilings |
| Dark green or black, powdery or velvety | Cladosporium and similar molds | Painted walls, fabric, air vents, around windows |
| Black or greenish-black, slimy when wet | Possibly Stachybotrys | Drywall, wallpaper, ceiling tiles after a leak |
The CDC names Cladosporium, Penicillium and Aspergillus as the most common indoor molds. Whichever it is, the answer is the same: remove it and fix the moisture.
Do I need to test black mold before removing it?
No. The EPA says that when you can see mold, testing is usually unnecessary, and there are no federal limits to test against. The CDC does not recommend routine mold testing either. Testing can help in specific cases, such as checking that an area was cleaned properly after remediation, or looking for hidden mold you can smell but can't find.
If a business wants to test before it quotes, ask what the result would change about the work. Our mold inspection and testing page explains when a test is worth paying for.
Can black mold be fully removed?
Yes, black mold can be removed so it doesn't come back, as long as the moisture that fed it is fixed. Mold can be scrubbed off hard surfaces like tile, glass and sealed wood. Drywall, ceiling tiles, carpet and insulation that are moldy usually have to be cut out and replaced, because mold grows into the material.
What a black mold removal job typically includes:
- an inspection to find the moisture source and how far the growth has spread, including behind walls
- containment, so dust and spores don't spread to the rest of the house
- removal of moldy drywall, insulation or flooring, and cleaning of the framing behind it
- drying, then fixing the leak or moisture problem
- repairs, which are often quoted separately
Spores are always in outdoor air, so "fully removed" means removing the growth and the moisture, not every spore in the house.
How much does black mold removal cost?
Black mold removal costs the same as other mold remediation, because the work is the same. Published figures put most jobs at about $1,200 to $3,750, with an average around $2,300, according to Angi data reported by This Old House in March 2026. Small bathroom jobs can be a few hundred dollars. Mold through several rooms or the heating and cooling system can run into five figures.
What makes black mold jobs cost more is usually where they are. Mold that grows after a leak is often inside walls or under floors, so drywall has to come out and be replaced. Ask each business to separate the mold removal price from the repair price. Our mold remediation cost guide has the full ranges.
Questions people ask
Is black mold powdery?
Black mold can look powdery or fuzzy when it is dry, and slimy when it is wet. Stachybotrys often looks wet and slick on soaked drywall. Powdery, velvety dark mold is often another common species such as Cladosporium. Texture alone won't tell you the type, and the CDC says you don't need to know the type to clean it up.
Is Cladosporium common in houses?
Yes. The CDC lists Cladosporium among the most common indoor molds, along with Penicillium and Aspergillus. It often grows on painted surfaces, fabric, window frames and around air vents where condensation forms. Like any indoor mold, it means there is too much moisture in that spot, and that is what needs fixing.
What kills black mold immediately?
Nothing kills mold in a way that solves the problem on its own. On hard surfaces, the EPA recommends scrubbing mold off with detergent and water and drying the surface completely. The CDC says a bleach solution of no more than 1 cup of household bleach in 1 gallon of water can also be used on hard surfaces. Never mix bleach with ammonia or other cleaners.
What are signs you are sick from black mold?
The CDC lists a stuffy nose, sore throat, coughing or wheezing, burning eyes and skin rash as common symptoms in people who react to damp, moldy places. People with asthma may have attacks. These signs are not specific to mold, so if they don't go away, or they are severe, see a doctor and mention the mold in your home.
Can I stay in my house while black mold is removed?
Many people stay home during a small or medium job, because the crew seals off the work area. For large jobs, or if anyone at home has asthma, allergies or a weak immune system, the business may suggest staying elsewhere until the work and cleanup are done. Ask about this when you get quotes.
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