How to Read Your Mold Test Results

Sep 29

Mold lab reports are full of Latin names and numbers. Here’s a plain-English guide to reading your mold test results, whether you had an indoor air quality test, a surface swab test or both.

First: there is no official “safe” mold number

The EPA notes that no federal limits have been set for mold or mold spores. Instead, air results are interpreted by comparing indoor samples with an outdoor sample taken at the same time, and by looking at which types of mold are present.

Reading an air sample report

Spore types. Each row lists a mold type (for example Aspergillus/Penicillium, Cladosporium, Stachybotrys).
Count per cubic meter. How many spores of that type were collected per cubic meter of air.
Indoor vs. outdoor. Healthy indoor air generally has similar types of spores to outdoors, at similar or lower levels. Red flags are indoor counts much higher than outdoors, or types present indoors that are absent or rare outside.

Reading a surface swab report

Swab results tell you what is growing on the surface that was sampled, often rated as light, moderate or heavy growth. A swab confirms whether a stain is actually mold and identifies the type. It doesn’t measure what’s in the air.

Common mold types you may see

Cladosporium: very common outdoors. Indoors it often grows on damp window frames and bathroom surfaces.
Aspergillus/Penicillium: common indoor molds, often linked to water damage or high humidity when elevated.
Stachybotrys: the so-called “black mold,” associated with materials that stayed wet for a long time.
Chaetomium: another indicator of long-term water damage, often in drywall.

What to do with your results

Results look normal: keep humidity under control and fix small moisture issues promptly.
Elevated or water-damage molds found: find and fix the moisture source first. For areas larger than about 10 square feet, the EPA suggests considering a professional remediation contractor.
After cleanup: a follow-up test can confirm the air is back to normal.

We explain your results

Every Mold Test & Fix report comes in a clear, easy-to-read format, and we’re happy to walk you through it. Because we don’t sell remediation, our only job is to give you an honest answer. Pricing is flat: $399 first sample, $179 each additional. Call (310) 999-8772 or book online.

Bar Dror