How do I know if my home has mold?
Last updated September 3, 2026.
Your eyes and nose are the test: mold looks like spots in many colors and smells musty, and the CDC says seen or smelled mold should be removed. Hunt where moisture lives: under sinks, window frames, bathroom ceilings, basements, old leak sites. The EPA notes mold produces allergens and irritants that can trigger allergies and asthma and irritate airways even in non-allergic people, so symptoms that ease away from home are a hint. Skip the air test kit: the fix is the same whatever the species. Find and fix the moisture source, and treat anything beyond a small patch, roughly 10 square feet per EPA guidance, as a possible professional job.
What to do
- Inspect the damp zones: sinks, windows, bathrooms, basements, old leaks.
- Trust your nose; a musty smell with no visible mold means hidden growth.
- Fix the moisture first, or the mold returns.
- Consider professionals for areas over roughly 10 square feet or sewage damage.
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