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How to Test for Mold That’s Hiding In Your House

Close-up Of A Person Hand Wearing Gloves Checking Moldy Wall At Home
Andrey_Popov / Shutterstock

Mold is a serious potential health hazard that is commonly lurking in all kinds of buildings, residential homes included. Mold can trigger allergic reactions in certain people, causing stuffy sinuses, itchy eyes and skin, difficulty breathing, and even fevers. Other studies have linked the presence of mold in the home with the development of childhood asthma and pulmonary problems in otherwise healthy individualsBlack mold, known as Stachybotrys chartarum, is of particular concern due to possible links to acute idiopathic pulmonary hemorrhage in infants and other ill health effects.

Whether you’re experiencing some of the above symptoms or just want to know if your home is free of mold, testing for mold in your house is a fairly simple process. However, keep in mind — treating mold is a much more difficult process. If you’re wondering how to test for black mold, in particular, you should know that black mold tests need to be verified in a laboratory. Continue on to learn how to detect mold in your house.

How to test for mold in 6 steps

Mold infestations can usually be seen or smelled, but they can also remain hidden behind walls or under carpets. Testing isn’t necessary if you can see or smell mold — that is confirmation enough to call a professional and begin the remediation process. Testing for mold in the house may be necessary if requested by a health professional or needed for legal purposes, such as a lawsuit with a landlord. Another reason to consider testing is if you aren’t able to see or smell mold in your home but are having unexplained symptoms associated with mold. Always follow the instructions provided with a test kit (more on that below), but this is generally what to expect:

Step 1: Perform a visual inspection

If you suspect you have mold, the first step is to perform a thorough visual inspection of your home. You will recognize mold as spots that can appear in many different colors. Mold thrives on moisture, so pay particular attention to roofs, windows, pipes, basements, laundry areas, bathrooms, previously flooded spaces, and so on. Mold commonly appears on fibrous surfaces like drywall, upholstery, wallpaper, fabrics, and cardboard. If you see any signs of mold, call a professional.

Step 2: Purchase an at-home test kit

If you do not see any mold but want to check for sure, order an at-home test kit. You may also want to order a kit if you see mold and need to identify it for health or legal reasons. You can either order a test kit that includes testing with the price, such as a DIY Mold Test, or a test kit with optional lab testing such as the Mold Armor Do It Yourself Mold Test Kit. The latter is best if you are only interested in confirming the presence of mold, and aren’t concerned with identification.

Step 3: Prepare the growing medium

Most test kits use a petri dish and a mold growing medium. Follow the product instructions for preparing the petri dish.

Step 4: Collect your sample

There are a few different ways to collect a sample using a petri dish. The first is an indoor air quality method in which you leave the dish on a flat surface for one hour and then cover it with the lid. If you want to check for mold in your HVAC system, tape the dish to an air duct and blast the air for ten minutes, then cover your dish. The final method is to use a swab to wipe visible mold and then wipe the swab onto the growing medium. This method is best if you can see the mold.

Step 5: Check your petri dish

After 48 hours, check your petri dish for signs of mold growth. If you do not see mold, wait another 24 hours and check again. If you still don’t see mold, wait again for 24 hours and check one last time. If you do not see mold growth after 96 hours, your test did not detect any mold. If you do see mold on your test plate, you should take additional steps to remove the mold.

Step 6: Send your sample for identification

Follow the provided instructions for sending your sample to the lab to be tested. Remember, some test kits include laboratory testing in the price of the product itself, while other kits require an additional fee if you want your samples identified.

Products and tools you’ll need to test for mold in your home

The only thing you need to test for mold at home is a test kit. In addition to the ones previously mentioned, there are several options available:

  • Pro-Lab Mold Test Kit: This kit includes three tests. Your sample can be tested for an additional $40 fee, with results delivered by e-mail or via the company’s app.
  • MoldCheck Multi-Test Kit: This kit includes supplies to perform ten tests, which is great for an entire home or monitoring an ongoing infestation. However, there is no lab testing option, so you will need to find your own if you need identification.
  • ImmunoLytics Mold Screening Test Kit: Perform eight tests with this kit. Each plate can be tested for $33 each.
  • My Mold Detective: If you are looking for a more advanced mold monitoring option, the My Mold Detective is a reusable air sampling pump that collects samples in just five minutes. The device comes with four sampling cassettes that can be tested in a lab for $35 each.
  • My Mold Detective Additional Samples: The My Mold Detective can be used again and again, so order as many samples as you need to keep tabs on your mold problem.

Don’t want to use chemicals? Here’s how to test for mold in your home naturally

If you’re concerned about the effects of harmful chemicals when testing for mold in the house, worry not. Testing for mold doesn’t use any chemicals, and kits are non-toxic.

In fact, the main thing you should be worried about when testing for mold is the mold itself. If you are collecting direct samples of mold using the swab technique, wear gloves and a mask to reduce your exposure to the mold.

The bottom line on testing for mold

The cleanup procedures for treating mold are the same, whether it is black mold or another type, so it isn’t always necessary to test for mold if you can see or smell it. But if you have a specific reason for identifying types of mold in your home or suspect you have mold but can’t find the source, a do-it-yourself mold test is extremely easy to conduct.

Frequently Asked Questions

Is mold dangerous?

Yes, mold is potentially harmful to human health. The presence of mold can trigger allergic reactions and cause respiratory problems in healthy individuals.

How often should I test for mold?

Generally speaking, you do not need to test for mold unless you have a specific reason, as mold infestations can usually be seen or smelled.

What are common health problems associated with mold? 

The most common health problems caused by mold are allergic reactions such as a stuffy nose, itchy eyes, or wheezing. Mold has also been linked to more serious conditions, such as acute idiopathic pulmonary hemorrhage in infants, asthma, and other pulmonary conditions.


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