Color is not a species test
Many people assume dark mold is one specific dangerous type. The EPA is clear that color cannot be used to identify a mold species. Many molds appear black, green, gray, or white depending on the material and conditions.
Two patches of the same color could be entirely different organisms.
What color can suggest
Color can help you notice growth and track whether it is spreading. Fresh staining in a new area can indicate moisture is still present. That is useful information, even without knowing the species.
When testing helps
Sampling and lab analysis can identify molds. That can be useful for documentation, real estate decisions, or disagreements between landlords and tenants.
The EPA also notes that when growth is visible, sampling is often not necessary to decide on cleanup. Visible growth should be addressed either way.
The response is the same
Regardless of color, the steps are consistent: find and fix the moisture source, remove affected porous materials like carpet and pad when they have growth, and dry the area.
Health concerns are valid. Mold exposure can cause allergic reactions and irritation in some people. Anyone with health concerns should speak with a medical professional.
Talk it through
If you have found dark growth under your carpet, avoid disturbing it and call (855) 661 4275 Monday to Saturday, 8am to 7pm.
This guide is general information about carpet mold based on publicly available EPA guidance. It is not a substitute for an assessment of your property or medical advice.