Home Healthy Home The White Towel Test: 7 Steps to Test How Much Mold is Tracked into Your Home

The White Towel Test: 7 Steps to Test How Much Mold is Tracked into Your Home

by Catherine

Today, I am going to share a simple but very effective experiment anyone can do in their own home. This experiment is used for the sole purpose of showing you just how much dirt, mold and bacteria is tracked into your home each day on your shoes. Kind of a gross idea, but one that is very effective, especially if you are trying to convince friends or family members that cleaning for mold is a necessary endeavor. And, let me be clear, I am talking about just everyday tracking here, folks. This is totally separate from mold and bacteria that are introduced to an indoor space by a leak, water intrusion, dampness in a crawlspace, or mold in an HVAC unit. This is “everyday” mold. It can enter into ANYONE’S home, regardless of how clean it is.

Before I give you the 7 steps, I want to say that this “experiment” is NOT scientific. It just uses an everyday, real scenario to exemplify the fact that more dirt, mold and bacteria enter your home via your shoes and feet than you might be aware of.

Ready to test? Here you go!

The 7 Step “White Towel” Test:

Step 1:  Choose the door that you use most to come and go from in your home. For our family, this is our back door.

This is our most-used door. As you can see, we have a no shoes policy in our home, so shoes are frequently kicked off right by this door. This won’t affect your results on this experiment, though, so keeping reading!

Step 2:  Place a white towel just in front of that door on the inside of your home. I actually encourage you to place the towel just beyond your floor mat. In other words, have your floor mat come first as you walk in the door, and then place the white towel where you will step AFTER the floor mat. This will further show you that even when you swipe your feet on the mat, you are still tracking in a large amount of dirt and mold.

Step 3:  Take a picture of the towel on Day 1 before anyone steps on it, when it is nice a sparkling white.

Step 4:  Make sure that you or your family members step onto the white towel each time upon entering or exiting your home for the next 2-3 days. (Note: If you don’t have kids or a pet, I would leave it for 3 days.)

Step 5:  At the end of Day 2 or 3, take another photo of the towel.

Step 6:  Compare your pictures.

Fresh Towel
Day 1
Day 2
Day 3


Step 7:  Marvel at the amount of dirt, mold and grime on your white towel after just 2 days!

Can you believe the simplicity of this experiment? The first time I did it was because Dr. Dennis had encouraged me to become more aware of the mold entering my home—we had professionals remediate everything, then had conducted air and surface testing that came back “clean,” but I was still having mold allergy problems. After I did Dr. Dennis’s “white towel test,” I recognized what was happening: We were tracking outdoor mold inside and onto the rugs, etc.  Because of the insight gained through this simple test, I was able to make the changes of 1) having everyone remove their shoes upon entering our home, and 2) using the EC3 products, like the EC3 Mold Solution Spray and EC3 Laundry Additive on a daily basis to clean the surface and superficial mold from our things and clothing before it could become an allergy issue for me. Problem solved!

Let me know if you decide to do this experiment yourself. I would love to hear from you and to see your pictures!

Share this:

You may also like


Mari August 16, 2017 - 1:26 am

Of course the towel is going to get dirty. That’s a “duhhhh!” How do you know there’s mold on the towel? I have a pet that can come and go at will, have used towels on my carpet on the high traffic areas for years, then wash them & use them again. I don’t see what this test is telling me other than we have dirty feet. Sorry. I was hoping for more.

Catherine August 16, 2017 - 2:26 pm

The main idea is increasing awareness of just how much dirt, mold, bacteria, etc. from the outside is tracked directly into your home in a very short amount of time. Any outside dirt, because it is organic material, contains mold. Thank you for your comment, though, because it alerts me to the need to do a follow-up post on this subject. I will do TAP tests on the towels and post the results to show how much mold grows out on the testing material just from what is tracked in by your shoes. I hope you will keep an eye out for that post, so that you will find the more in-depth information you were hoping for.


Leave a Comment