By Doug Hoffman

Whether mold tests indoors are necessary is an important idea to explore because the answer has changed over the years and, I think, to the better. Traditionally, we have taken the position that mold testing is unnecessary — that if you see mold you just clean it up, no questions asked. That’s quick and simple but could be problematic for a variety of reasons.

Mold is ubiquitous: A very big word for just saying that mold is everywhere. Its presence outdoors is not much of a problem because it is diluted by the huge volume of air. Indoors is another question because our environments are tightly sealed, and much of the air is turned repeatedly with very little fresh air coming in from the outside to dilute it. Mold spores settle on a surface, find a nutrient and a little moisture, and voila, you could have a problem.

But can you tell if it is mold without mold testing? The answer is no. It might look like mold but could be insect remains, feces, or just generic dirt.

The EPA has an interesting document that we show in our classes demonstrating the confusion and disconnect that has plagued our industry. “If you see mold, just clean it up” this document starts. Then the very next sentence suggests, “if litigation is likely, you might consider testing.” In the very next paragraph, the document concludes by saying, “the only way to tell if it’s mold or dirt is to test it.”

So, might it be important to know whether you’re dealing with mold or dirt? The answer is yes.

Why perform mold testing?

Knowing the difference between mold and dirt might help a doctor better diagnose symptoms someone has because of environmental sensitivity. Some doctors prefer to know the specific genus of the mold, so they can treat the symptoms, and that certainly can’t be determined by the naked eye.

A trained National Organization of Remediators and Mold Inspectors (NORMI) Certified Mold Assessor would want to know the genus to help determine where the water source might be. They might ask, “Is this mold I’ve identified getting its moisture source from behind the drywall, from an air infiltration issue, or from the relative humidity?”

The first place to start for the assessor is to know, for sure, that what he is dealing with is mold. A trained NORMI Certified Mold Remediator would want to sample the mold to make sure he’s created a baseline for his own files to which he can compare his PRV (post remediation verification), confirming that he has substantially reduced the mold growth in the areas that were remediated or sanitized.

The industry is changing. NORMI has led the way by writing the NORMI Professional Practices, which require all mold professionals to test what looks like mold. A particular YouTuber claims you can tell whether something is mold simply by licking it. Yes, licking it. Though it makes me chuckle, it’s about as ridiculous as thinking you could tell by simply looking at it.

The trained mold professional takes both air and surface samples to determine the type of mold, the amount of mold, and the source of the moisture that’s feeding it and creates a baseline for future testing. Without testing, each one of those processes is simply a guess — and probably not a very good one!

Doug Hoffman is the CEO of NORMI, the National Organization of Remediators and Mold Inspectors. He can be reached via e-mail at