There is a musty smell or visible mold
A persistent musty odor, past water damage, or visible growth.
A musty smell often means mold is growing somewhere, even when you cannot see it. Air sampling sent to an accredited lab is more representative than a settle-plate kit. If you find a large area of growth, or the home had significant water damage, consider a professional assessment before any remediation.
What to do
- Use a mold test. Air sampling is more reliable than settle plates.
- Send samples to an accredited environmental microbiology lab.
- For large growth or major water damage, get a professional assessment first.
Common questions
Can I have mold without seeing it?
Yes. A persistent musty smell often means mold is growing out of sight, such as behind walls or under flooring. Air sampling analyzed by an accredited lab is more representative than a surface kit.
Are DIY mold test kits reliable?
Settle-plate kits can confirm mold is present but do not reliably measure how much or which type. Air samples sent to an accredited environmental microbiology lab give more usable results.
Should I test the mold or just remove it?
A small visible patch can often be cleaned directly. For large growth (roughly 10 square feet or more) or after major water damage, get a professional assessment before remediation.
Where to go next
General information to help you find the right test and an accredited lab. This is not medical, legal, or safety advice. For a confirmed exposure or a health concern, talk to a qualified professional, and always confirm a lab's current accreditation with the certifying body.
Back to all concerns