How to Test for Black Mold

One of the scourges of high-humidity climates, black mold is highly toxic and should be removed as quickly as possible. There are various ways to test for and detect black mold, from sight to smell to special mold kits. There are four types of mold that tend to affect homeowners: black mold, white mold, yellow mold and green mold. Black mold is the most toxic. If you think you have a black mold problem, you should test for it immediately.

Testing for Black Mold by Sight

Black mold looks like splotchy dark gray blooms proliferating on walls, floors and furniture. It typically grows in dark, damp, out-of-the-way places. If it is allowed to grow, it will eventually enter your ventilation system and may attach to surfaces all over your house. Therefore, you should check every potential mold hiding place in your house. Common locations for black mold include:

  • Under carpeting
  • In basement corners
  • In crawlspaces and attics
  • Behind washer/dryers
  • Behind wallpaper
  • Between bathroom tiles
  • In gutters
  • Behind pipes

Sight-testing for black mold is unfortunately not a perfect method. Mold may be present but not visible, or you may mistake simple water damage for mold on a dark surface.

Testing for Black Mold by Smell

If you can smell black mold in your house, your health is likely at risk. Black mold has a distinct dried-urine smell that can be quite strong depending on the intensity of the proliferation. If you smell the musty urine scent as a diffuse odor throughout your house, you may have mold growing in your vents or in multiple places. If this is the case, you should definitely call a professional to remove it.

Testing for Black Mold by Kit

You can purchase a mold kit from most hardware stores. Mold kits allow you to take a swab of the affected surface, send it in to a lab and receive a report indicating what it is.

The kits typically consist of a petri dish, a sterile cotton swab and some sort of growing medium like agar.

Place the medium in the petri dish and wait about an hour for it to stick to the bottom. Acquire eye, face and hand protection. You will be getting very close to the toxic mold and you don’t want to breathe any in.

Go to the location of the mold and gently rub it with your sterile swab. Make sure you get a visible bit of the mold on the swab, but don’t spend too much time trying to get a good sample. The lab only requires a small amount of sample for accurate test results. Be very careful about disturbing the mold, as this may cause it to spread to other areas in your house.

Once you have a sample on your swab, gently transfer the sample to the petri dish. Mail the dish to the lab recommended by the kit. You will likely receive your black mold test results within a couple weeks.

Leave a comment