Are home mold test kits accurate? What CDC and EPA say about testing

Are home mold test kits accurate?

A kit can be accurate about what landed on its dish and still give you a useless answer. The problem is the question it answers.

Mold spores are part of normal indoor air. EPA says it is impossible to get rid of all mold spores indoors, and “some mold spores will be found floating through the air and in house dust.” So a settle-plate kit, a petri dish you leave open in a room, will almost always grow something. That tells you mold spores exist, which was never in doubt.

The Minnesota Department of Health puts it plainly. A complex mix of mold particles “normally exists in all occupied indoor environments,” and even when testing is done well, it “may not be able to distinguish between ‘normal’ and ‘problem’ conditions and it may even give misleading results.”

Kit-specific weaknesses add to that:

• No interpretation. EPA says sampling should be designed and interpreted by professionals with specific experience. A kit leaves the reading to you.
• Contamination. Bob Vila’s 2025 kit review, which recommends several kits, still says swab and tape tests “can be susceptible to contamination and false results,” and that petri dishes left open too long can pick up airborne contaminants.
• Hidden costs. The same review lists kit prices from $10 to $300, with some charging lab fees on top, such as $39 per sample for one brand.

For identification without a kit, see signs of mold, or start at the mold hub.

Why doesn’t CDC recommend mold testing?

CDC says directly: “CDC does not recommend mold testing.” It gives three reasons.

1. People react differently. “The health effects of mold are different for different people so you cannot rely on sampling and culturing to know whether someone might become sick.”
2. Good sampling costs money. CDC notes “good sampling for mold can be expensive.”
3. There is no standard. “There are no set standards for what is and what is not an acceptable quantity of different kinds of mold in a home.”

CDC’s conclusion is that “the best thing you can do is to safely remove the mold and prevent future mold growth.” CDC also says “no matter what type of mold is present, you need to remove it.”

State health departments agree. The Florida Department of Health “does not recommend mold testing or sampling to see if you have a mold problem.” The Minnesota Department of Health says it “usually does not support mold testing as the first response to indoor air quality concerns.” The federal guide written after Hurricane Sandy by EPA, CDC, FEMA, HUD and NIH says sampling “is not usually recommended.”

What does EPA say about mold testing?

EPA’s position is slightly different from CDC’s but leads to the same place. EPA says “in most cases, if visible mold growth is present, sampling is unnecessary.” It adds that because no EPA or other federal limits exist for mold or mold spores, “sampling cannot be used to check a building’s compliance with federal mold standards.”

EPA does name uses for sampling:

• Surface sampling “may be useful to determine if an area has been adequately cleaned or remediated.”
• Sampling should be done “by professionals who have specific experience in designing mold sampling protocols, sampling methods, and interpreting results.”
• Lab analysis should follow methods from the American Industrial Hygiene Association (AIHA), the American Conference of Governmental Industrial Hygienists (ACGIH) or other professional organizations.

EPA also says it has no certification program for mold inspectors and keeps no list of them. Its advice: “Mold assessment is mainly done through visual inspection of areas where there have been moisture problems or water damage.” Testing “may be of limited use in helping to understand the problem.”

What is ERMI, and should you use it?

ERMI stands for Environmental Relative Moldiness Index. EPA researchers developed it to describe the mold burden in a home against a national sample of indoor mold values. It relies on an EPA-patented DNA lab method called mold-specific quantitative PCR (MSQPCR). Some companies sell ERMI tests directly to homeowners. See the ERMI glossary entry for more on how it works.

EPA’s answer to whether you should use it is one word: “No.” EPA says ERMI “is a research tool and is not recommended for use except as a research tool.”

A 2013 EPA Inspector General report found that firms were using ERMI to evaluate homes even though EPA had not validated it for public use. The report says EPA “readily acknowledged that it had not validated or peer reviewed” the method or ERMI for public use. It warned the public “may make inappropriate decisions regarding indoor mold” if they believed ERMI results were EPA-endorsed.

If someone offers you an ERMI score, ask what decision it will help you make. A visual inspection and moisture check will answer most of the same questions for less.

Kit vs professional testing: how do they compare?

Can a mold test tell you if the mold is “toxic”?

No. CDC says you do not need to know the type of mold, and that every type should be removed. The Minnesota Department of Health lists “to learn if the mold is the toxic kind” as a poor reason for testing. It explains that molds able to produce mycotoxins may or may not be producing them, and that finding such a mold “does not necessarily indicate that known mycotoxins are also present or that occupants will be harmed.”

Home kits do not measure mycotoxins at all. Urine mycotoxin tests sold to consumers are a separate product. AAAAI says those tests are not FDA-approved, lack standardization and have no established thresholds for harmful levels. Our page on mycotoxin testing covers why.

When is a paid mold inspection worth it?

Testing is rarely the first step, but a professional inspection, which may include sampling, can be worth the money in specific situations.

Not worth it: confirming mold you can see, finding out whether it is “black mold,” or judging whether your home is “safe.” The Minnesota Department of Health says it is a “common, yet serious error to conclude that a mold problem does not exist simply because tests failed to find evidence of it.” Testing is never a substitute for a thorough visual inspection.

HomeAdvisor (updated 2026-06-19) puts the average inspection at $689, with a typical range of $303 to $1,075, and air sample lab testing at $250 to $350. See mold inspection costs for more.

How do you hire an independent mold tester in Florida?

Florida licenses mold assessors and mold remediators separately through the Department of Business and Professional Regulation (DBPR). Verify any license on the DBPR site before you hire.

Florida also protects you from a built-in conflict of interest. Under Florida Statutes 468.8419, a mold assessor may not perform or offer to perform remediation on a structure the assessor or the assessor’s company assessed within the last 12 months, with a narrow exception for certain licensed contractors. The same law bars assessors from paying or accepting referral fees with remediators.

Outside Florida, ask about training, experience and references, and choose a tester who does not sell remediation. See mold assessor vs remediator for how the two roles work together.