Mold testing FAQ

As a rough estimate, a professional mold inspection often runs about $300 to $1,000, and lab fees for surface samples are commonly $50 to $150 each. Prices depend on home size, how many samples are taken, and where you live. Get local quotes to confirm. See our cost guide for the full breakdown.

Usually not. The EPA says sampling is generally unnecessary when mold growth is visible. Fix the moisture source and clean or remove the mold.

An inspection is a visual check with moisture meters and often a thermal camera. A test is a sample of air, a surface or a material that goes to a lab. Most jobs start with an inspection.

Settle-plate kits almost always grow something, because mold spores are in nearly all indoor and outdoor air. Without a measured air volume and an outdoor comparison, a positive result doesn't tell you much. A swab sent to a lab can identify what a visible spot is.

There are no EPA or other federal limits for mold or mold spores. Inspectors usually compare indoor air samples to an outdoor sample taken at the same time.

Mold can start growing on wet materials within 24 to 48 hours, which is why the EPA recommends drying wet materials within that window.

The EPA says homeowners can usually handle an area under about 10 square feet, as long as the moisture problem is fixed. For larger areas, HVAC systems or sewage-contaminated water, hire a professional.

The EPA recommends keeping indoor humidity below 60%, ideally between 30% and 50%.

According to the CDC, people sensitive to mold may get a stuffy nose, wheezing, red or itchy eyes, or skin irritation. People with asthma or mold allergies can react more strongly. Talk to a doctor about health concerns.