First Steps After Discovering Mold

Step one: find the moisture source

Mold needs sustained moisture to grow. Before you clean anything, look for the cause: a slow plumbing leak, condensation on a cold surface, a roof leak, or high indoor humidity. The EPA states directly that if you clean up the mold but don't fix the water problem, the mold most likely comes back. Fixing the source is not optional if you want the cleanup to last.

Step two: size up the area

The EPA's threshold is specific: if the moldy area is less than about 10 square feet, roughly a 3-by-3-foot patch, in most cases you can handle the cleanup yourself. Larger areas, or mold following a significant water event, generally call for a professional contractor experienced in mold cleanup.

Step three: don't run the HVAC system if you suspect contamination

If you think mold has reached your heating, ventilation, or air conditioning system, the EPA advises not running the system, since it could spread mold spores throughout the building. Have the system inspected before turning it back on.

Step four: skip testing, focus on removal

The CDC states you do not need to know the type of mold present to clean it up safely, and the agency does not recommend mold testing as a prerequisite. If a company's first pitch is a paid testing package before any remediation plan, that step is not something CDC guidance calls necessary for safe cleanup.

Step five: protect yourself if you're cleaning a small area

For small areas within the DIY range, the EPA recommends scrubbing mold off hard surfaces with detergent and water, then drying the area completely. Discard porous materials like carpet or ceiling tile if they are heavily moldy, since they generally can't be fully cleaned. Don't paint or caulk over mold before cleaning and drying the surface first, since paint over mold does not solve the underlying problem.

When to call a doctor instead of, or before, a contractor

If you or someone in the home has asthma, a mold allergy, a compromised immune system, or chronic lung disease, the CDC notes these groups face a higher risk of symptoms or infection from mold exposure. Consult a health professional about symptoms before or alongside starting cleanup, particularly for a larger-scale problem.

Should you file an insurance claim first?

That depends on the cause. Mold that follows a sudden, covered event, like a burst pipe, may be covered as part of that claim. Mold from long-term moisture, humidity, or an uninsured source like flooding typically is not covered under a standard Michigan homeowners policy. See "Does homeowners insurance cover mold?" for the coverage breakdown before you assume it's reimbursable.

Document before you clean, even for a small area

Even a DIY-scale cleanup within the EPA's 10-square-foot range is worth photographing first, especially if you plan to file any kind of claim tied to the water event that caused it. A photo of the affected area before cleanup, plus a note of when you first noticed it, gives you a record you won't be able to recreate once the area is scrubbed clean.

What a professional assessment actually adds beyond what you can do yourself

For an area larger than the EPA's DIY threshold, a professional's value isn't just labor, it's containment to keep spores from spreading to unaffected rooms during removal, and equipment like negative air machines that aren't practical for a one-time homeowner job. If you're on the fence about whether your situation needs professional help, the size of the area and whether it followed a significant water event are the two clearest deciding factors.