How to Test a Sauna (and Document What You Find)

You cannot rely on an inspector who does not exist. How to look, where to look, what a consumer swab kit can and cannot tell you, and how to build a record that agencies and journalists have to take seriously.

In most of America, nobody official is going to test the sauna at your gym — the regulatory gap means there is usually no inspector to call. That is how our founder ended up doing it himself in August 2024. Here is the method, generalized from his case, so you can do it better documented than he had to.

1. Look where the sweat goes

• Under and behind the benches. This is where sweat drips and pools, and where growth concentrates. If the bench is fixed to the wall, ask the question Thomas asked: how would anyone clean under there? If there is no access panel, that is a finding all by itself — write it down.
• The bench enclosure and ceiling of the bench box, floor corners, and anywhere wood meets tile.
• Check for a floor drain. No drain in a wet room is a design defect worth photographing.
• Steam rooms and showers: grout lines, shower heads, and any surface that never fully dries.

2. Photograph and film everything, with dates

Thomas’s most durable evidence was not the test kit — it was video, on camera, timestamped by publication. Film the growth, the bench construction, the missing drain, and your own testing, in one continuous record. Keep the originals.

3. Use a consumer swab kit for what it is good for

Consumer kits (the Mold Armor kit Thomas used is one) swab a surface and lab-identify what grows from it, typically to genus level. Used honestly, they tell you:

• What organisms are present — in his case Chaetomium spp., Aspergillus spp., and Nigrospora spp., all recognized dampness-associated molds.

What they do not tell you:

• A dose, a spore count in the air, or whether a specific illness was caused by the room. A swab result is evidence of presence and neglect, not a medical conclusion. Do not oversell it — the record is stronger when every claim in it is exactly as big as the proof.

4. Put it in writing, everywhere, and keep the receipts

Thomas filed with the gym and its corporate parent, the franchise owners, the state attorney general, the governor, the business regulator, the consumer-services agency, the BBB, the health department, and code enforcement — in eight days. File in writing, keep copies and case numbers, and note every response (including silence, with dates). Then take it to the Report It page for your state’s exact routes.

5. If you got sick, treat the medical side separately

Document symptoms with dates, see a medical professional, and tell them about the exposure specifically. Medical records and facility records are two different trails; you want both, and neither substitutes for the other.