There is an easy and cheap test that is actually accurate. You place Petri dishes with a specific medium in them in the room, open, for an hour. Then you close them and put them in a dark spot for a week. When you next look at them, count the colonies that have formed. 3 or 4 or below is fine. 3 to 6 or 7 you need to wipe the walls with citrus oil cleaner or diluted bleach, deep clean carpets, remove old books and otherwise deep clean the space. More than that, you likely have mold issues in the walls or ceiling or floors. All mold issues come from water sources- small leaks in plumbing, old seals around the edges of bathtubs, ingress from clogged gutters backing up, etc. here’s where you can get the petri dishes- https://immunolytics.com/store/ Don’t bother with the kit or with paying them to interpret results, just count colonies like I outlined above.

We are going through this now. It’s no fun at all. We have the house ripped down to the studs. A couple times the plates saved us, showing there was more mold then we’d thought. We’d rip out some stuff we’d found, run the test, find too many colonies on the plate then dig some more only to find more issues. Finally, we are getting clear plates, and I feel much better.

If it does turn out to be mold and fatigue caused by the mold feel free to contact me as I have been through it and am now on the mend. It’s a long difficult process with only the vague signals you mentioned to guide you.

Please don't direct people to that website selling overpriced petri dishes, "expert consult" services, and using scare tactics to convince people to order their expensive tests.

> count the colonies that have formed. 3 or 4 or below is fine. 3 to 6 or 7 you need to wipe the walls with citrus oil cleaner or diluted bleach, deep clean carpets, remove old books and otherwise deep clean the space.

Mold spores are everywhere in the air. This is not an accurate test at all. It's a random number generator. The thresholds don't even make sense: 3-4 is fine but 3-6 means throw out your books and deep clean the house?

If you want professional mold testing services, please start by looking up your local health department and seeing who they recommend for testing.

Most importantly, don't buy anything or take any advice from websites that have long lists of non-specific health symptoms that they claim are caused by mold. The lists of symptoms on that website include everything under the sun from headaches to sleep problems to acid reflux - https://immunolytics.com/understand-mold/ - This is how alternative medicine (and testing) sellers make their sales funnel as large as possible, not real science.

In the US where I live, professional mold testing companies have big expensive machines which supposedly count spores in the air. The results always come back negative, unless the space is visibly super contaminated. This is because mold is usually in the walls and these services are called in after a water issues to absolve landlords of financial responsibility for the extensive work and expense it would take to actually solve mold problems. It’s a nasty business.

We had our place professionally tested, got negative results, then tore the place down to the studs anyway (eventually, after the Petri dish tests described above) and found all sorts of mold.

Thanks a lot for sharing that.

Now that you say water sources, I just remembered she has a reverse osmosis water filter, and God knows the last time that filter was changed.

How would you go about testing the water or the filter with that method ?