Black Mold: What It Looks Like and How to Get Rid of It

There's no single mold called "black mold." The EPA says plainly that "black mold" is not a species or specific kind of mold, and neither is "toxic mold". The news media sometimes use those terms for molds that may produce mycotoxins, or for one specific mold, Stachybotrys chartarum.

So when someone says "black mold," they usually mean Stachybotrys. But plenty of other household molds are dark green, gray or black. The CDC notes that mold can look like spots of many different colors, and the EPA points out that molds come in many colors, including white.

Stachybotrys chartarum: the mold behind the name

The CDC describes Stachybotrys chartarum as a greenish-black mold that grows on material with a high cellulose content, such as fiberboard, gypsum board and paper. Gypsum board is drywall, which is why this mold often shows up on wet walls. It grows after water damage, water leaks, condensation, water infiltration or flooding, and the CDC says constant moisture is required for its growth.

That last point matters more than the color. If you find Stachybotrys, you almost certainly have a long-running water problem behind or under it.

You can't confirm the species by eye. Here is what you can reasonably notice:

Table: what black mold looks like in common spots around the house.

A few cautions. The EPA warns that paint on the back side of drywall or wood may look like mold growth, so not every dark mark is mold. And the EPA also notes that no one can tell whether a mold is producing mycotoxins just by looking at it.

Do you need to know if it's Stachybotrys?

Usually, no. The CDC says it is not necessary to determine what type of mold you have, and in Texas, TDLR says testing to determine what kind of mold is present is not required prior to remediation or cleaning. The plan is the same either way: find the water, fix it, and remove the mold. Our guide on how to test for mold covers the cases where testing does help.

Here is what the CDC actually says, without the hype:

• Stachybotrys chartarum and other molds may cause health symptoms that are nonspecific.
• At present, no test exists that proves an association between Stachybotrys chartarum and particular health symptoms.
• A possible link between this mold and acute idiopathic pulmonary hemorrhage among infants has not been proven, and the CDC says more study is needed.
• All molds should be treated the same with respect to potential health risks and removal.

In other words, black mold is not uniquely deadly, and a lighter-colored mold is not automatically safe. Mold in general can affect health. The CDC says exposure to damp and moldy places may cause a variety of health effects, or none at all. For some people it can cause a stuffy nose, sore throat, coughing or wheezing, burning eyes, or skin rash.

Some people face higher risk. According to the CDC, people with asthma or who are allergic to mold may have severe reactions, and immune-compromised people and people with chronic lung disease may get infections in their lungs from mold.

If you or a family member has symptoms that don't go away, see a doctor. The CDC says people with persistent symptoms should see their physician. A mold test of your house can't diagnose illness; only a medical professional can. Our black mold symptoms guide goes deeper on the health evidence.

The EPA's core rule is simple: the key to mold control is moisture control. If you clean the mold but leave the leak, it comes back.

Step 1: Find and fix the water

Look for the leak, condensation or flood damage feeding the growth. The EPA says to fix plumbing leaks and other water problems as soon as possible and dry all items completely. After any water event, dry water-damaged areas and items within 24-48 hours to prevent mold growth. Keep indoor humidity below 60 percent, ideally between 30 and 50 percent. In humid parts of Texas, a dehumidifier for mold can help.

Step 2: Decide if the job is small enough for you

The EPA says if the moldy area is less than about 10 square feet, you can usually handle it yourself. That's roughly a 3-by-3-foot patch.

Texas has its own line. TDLR says areas of visible mold of less than 25 contiguous square feet can be cleaned up by people who are not licensed. Anything bigger generally calls for a licensed company, and the EPA adds that contaminated sewage water requires a professional.

If you have health concerns, the EPA advises you to consult a health professional before starting cleanup. The CDC says people with asthma or who are immune compromised should not stay in a moldy home, or be there while it is being cleaned.

Step 3: Protect yourself

The CDC recommends that you wear at least a NIOSH Approved N95 respirator, protective gloves (non-latex, vinyl, nitrile, or rubber) and goggles that provide complete eye protection. Open windows or doors to let in fresh air when you use cleaning products.

Step 4: Clean or remove

Table: how to get rid of black mold by surface type.

Killing mold isn't enough on its own. The EPA notes that dead mold is allergenic and may cause allergic reactions, so the goal is to remove it, not just bleach it. For the full comparison of cleaners, read vinegar vs. bleach for mold.

Step 5: Check your work

When you're done, visible mold and moldy odors should not be present. If the smell or stains come back, there's still moisture somewhere.

Call a licensed mold removal (remediation) company when:

• The mold covers 25 contiguous square feet or more, the point where Texas generally requires a license.
• There's been significant water damage or mold covering more than 10 square feet, or sewage is involved.
• You suspect hidden mold. The EPA warns that removing wallpaper can lead to a massive release of spores and suggests hiring an experienced professional.
• Mold may be in your air conditioning system. The EPA says the HVAC system has the potential to spread mold throughout a building.
• Someone in the home has asthma, chronic lung disease or a weakened immune system.

Testing and removal are separate jobs in Texas

Texas law says a license holder may not perform both mold assessment and mold remediation on the same project. So if you want an inspection or a written plan first, hire a mold testing company for that, and a different mold removal company to do the work. Our guide on why testing and removal are different companies explains how that protects you.

Only a licensed company can give you the paperwork insurers and buyers ask for. TDLR says only a licensed remediator is authorized to give a Certificate of Mold Damage Remediation (CMDR). Before you sign anything, confirm the license with our license check tool. You can read how we verify every company daily against TDLR records.

Find licensed companies near you:

• Houston: mold removal and mold testing
• Dallas: mold removal and mold testing
• San Antonio: mold removal
• Austin: mold removal
• All cities: Texas mold directory

Wondering what it costs? See our mold remediation cost guide.