There are no federal standards for how much mold is harmful. There are also no national standards for mold inspection. Since there is not a clear "dose-response threshold" for mold (effects depend on several factors), it isn't feasible to establish mold level standards. Instead, mold assessments measure the difference between indoor and outdoor levels of the same types of mold at multiple times.
Testing for mold in a home is not usually recommended or useful, unless requested by a health professional, insurance company, or by a professional remediation contractor before and after clean up to offer evidence of the remediation's effectiveness. In these cases; according to the US EPA, sampling for mold should be conducted by professionals who have specific experience in designing mold sampling protocols, sampling methods, and interpreting results. Sample analysis should follow analytical methods recommended by the American Industrial Hygiene Association (AIHA), the
American Conference of Governmental Industrial Hygienists (ACGIH), or other professional organizations.
In general, if you can see it or smell it (musty odor), you have mold that needs to be remediated, so it won't grow and spread. Find the source of the moisture and fix the moisture problem, or the mold will grow again. Mold should be treated promptly as a potential health hazard.
Read more about mold in your home.
