When we last left off talking about mold, I shared my 25 proven methods for preventing toxic mold at home.

But what do you do if you’ve already lost the battle to mold – or at least suspect you have?  How do you know for sure?  In today’s article, I’m sharing my favorite ways to effectively (and inexpensively!) test your home for toxic mold growth.

Disclosure: This post contains affiliate links. If you purchase something through one of these links, I will earn a small commission while the price you pay remains the same. [Full disclosure policy] 


If this is your first time at the Wholesome Houses blog, welcome.  This is part 3 of a series, I’d highly recommend you start at the beginning of.  Don’t worry, I’ll wait:


How Do I Know If I Have Mold In My House?

While it is possible to do some investigating, “home forensics,” and other testing, positively identifying toxic mold can be difficult for many reasons:

  • High levels of toxic mold can be hidden from view and have little or no odor (think behind wood paneling or underneath linoleum in a bathroom)
  • According to Dr. Ritchie Shoemaker, symptoms of mold toxicity are widely misdiagnosed as diseases such as “fibromyalgia, chronic fatigue syndrome (CFS), multiple sclerosis (MS), depression, stress, allergies, post traumatic stress disorder (PTSD), somatization, irritable bowel syndrome (IBS), attention deficit disorder (ADD),” among others
  • In terms of symptomology, mold affects different people differently – this means that some people in same the home may seem completely unaffected, making accurate diagnosis even more difficult


How Do I Test My House For Mold?

Hate to say it, but the truth is, every house is different.  If you see mold, there is no need to start with sniff testing, for instance.  You obviously have a mold problem.  But for most people, starting with a simple sniff test and visual inspection around the house is a great place to start.  Please just use some common sense here.  Mold can be extremely dangerous.

In this article, I’m going to offer my general recommendations, but please seek professional help if you are seriously concerned about mold or if your test has positively identified the presence of mold.  Also, if you are uncomfortable conducting your own mold investigation, if you are unable to properly eliminate mold toxins, or if you or someone in your home has asthma or allergies, I highly recommend soliciting the services of a trained mold professional.

There are several home mold tests ranging from air and dust sampling to having occupants take an online vision test (I’m totally serious!), but not all of them are created equal.  These are my favorite mold tests, in the order I generally recommend them:


Sniff Testing

When it comes to mold, the nose knows!  So the big question is, what does mold smell like?

“Earthy” and musty odors are tell-tale signs that you have a mold problem.  You may have smelled it in an unfinished basement, storage unit, or inside a washing machine.

Start by taking a few minutes to inspect your home with your eyes and nose.  Start in the lowest level of your home, especially in basements and crawl spaces.  Also check wet areas of the home, including kitchens, bathrooms, and laundry rooms.  Be sure to smell furniture, water-based appliances, and rugs.

(Wholesome Tip: Suspect mold in your wall cavities? Sniff your dead electrical outlets.  If one smells musty, remove the outlet plate and use a flashlight to look into wall cavity)

If you smell that familiar musty smell, you more than likely have mold present, so move ahead to one of the more advanced testing strategies (if you find the mold, may I suggest DIY Tape Testing?).


 Sniff Testing ProsSniff Testing Cons
  • This method is totally free and can be done by any member of the family (including your four-legged friends!)
  • Doesn’t require expensive equipment or training
  • For the ~20% of the population who cannot properly detox from mold and mycotoxins, using their nose as a locating tool may be harmful to health
  • Certain locations (such as behind drywall and underneath vinyl flooring) are difficult to access for a sniff test or visual inspection
  • It can sometimes be difficult to find odors in your own home because of “olfactory adaptation,” or the experience of getting used to a bad or unusual smell


Visual Inspection

Because mold proliferation requires moisture, the next “mold test” that people should do in their homes is to perform routine visual inspections for mold, moisture, and water leaks.  I recommend a thorough inspection twice per year, scanning your home for signs of water damage inside and outside of the home.


Where Do I Inspect for Mold?

  • Start at the roof, visually inspecting for damaged shingles or flashing
  • Look inside the attic for water spots on the ceiling or floor
  • Look for water spots on ceilings in all rooms of the home
  • Check sink pipes for damage and leaking
  • Be sure to check the top 10 places toxic mold is hiding in your home


 Visual Inspection ProsVisual Inspection Cons
  • Free testing protocol that is effective in some circumstances
  • Doesn’t require expensive equipment or training
  • Because toxic mold can be hidden, it is fairly common to get a false negative based on a visual inspection – if you suspect mold, do not rely only on this method



Moisture Testing

A lot of times people think that mold testing and moisture testing are synonymous, but they are not.  In fact, when it comes to accuracy, cost, and usefulness, moisture testing trumps mold testing every time.  Here’s the scoop…


Mold Testing Vs. Moisture Testing: What’s The Difference?

According to Reuben Saltzman, “Moisture testing is done on exterior walls to determine if there are moisture problems behind the siding. The vast majority of moisture problems in walls are the result of bulk water intrusion, which typically results from water getting into the wall sheathing around windows, or through improper flashing at other penetrations such as roof ends and deck ledgerboards. Water intrusion at exterior walls typically involves expensive repairs, with stucco, and stone veneer siding being the most expensive types, and the most notorious for leaks. These wall coverings are expensive to install, they’re difficult to take apart, and hold a lot of water… Vinyl siding is the easiest siding to repair; it comes off quite easily, the damage caused by water intrusion on vinyl siding takes a longer time to get really nasty because vinyl “breathes”, and the same pieces of matching vinyl siding can be put right back up on the wall after repairs have been completed.”

And when it comes to mold testing, Mr. Saltzman says, “don’t bother.


Mold Testing Vs. Moisture Testing: Which Is Better?

According to the guys over at Hayward Score, “If you want to test for something, test for what causes mold in the first place: moisture. Mold will not – cannot – grow unless there is sufficient moisture for a sufficient time. Mold spores only germinate in the damp spot, and only if it stays damp for anywhere from 2-3 days to as long 2 weeks for Stachybotrys, for example. Also, mold is not the only hazard that can come from dampness. Bacteria flourish in damp conditions. Insects and rodents are drawn to long-term dampness. Chemicals (VOCs) are released from damp or damaged materials. Mold tests cannot detect any of these other pollutants. Testing only for mold will give a false impression that the other risks don’t exist. Finding and eliminating all possible sources of ongoing moisture is your best solution for solving the problem.”

 Moisture Testing ProsMoisture Testing Cons
  • Many toxic conventional building materials offgas volatile organic compounds (VOCs) when damp
  • In addition to preventing mold, stopping moisture and leaks in the structure of the house can prevent bacteria, insects, rodents, and other pests from colonizing home
  • Can be expensive depending on the exterior of home (stucco and stone veneer siding are the most costly)
  • Typically needs to be performed by a professional


Mold Sabbatical

It is my understanding that the idea of the mold avoidance sabbatical was first described by Lisa Petrison, an author and blogger who teaches others how to heal from toxic mold exposure.  The idea is simply to get away from your moldy environment and see what happens.

Of course, in practice it’s a little trickier.  First, there are occasional risks of mold avoidance, including passing out, paralysis, inability to speak, seizures, and suicidal inclination upon re-exposure to mold.  Second, it is also important that your sabbatical be at a location that is known to be mold-free.  Exposure, even at small levels, can prevent this type of elimination-style testing from being accurate.


 Mold Avoidance ProsMold Avoidance Cons
  • This is a great way to see if several members of your family are affected while enjoying a beautiful getaway
  • Doesn’t require expensive equipment or training, in fact, it really only requires a swimsuit, tent, or snow skis
  • Ideally, the mold sabbatical should last 2-3 weeks, which is a significant amount of time off of work/school/etc.
  • It can be difficult to find a 100% mold-free location to prevent low-level exposure during the sabbatical (and, in turn, effecting the test results)
  • Mold avoidance can be inherently dangerous and should be done under the care of a trained professional


Visual Contrast Sensitivity Testing

Woman's Eyes - Vision Test For Mold Related Illness

The Visual Contrast Sensitivity (VCS) test is a free online vision test that you can take from your home.  It’s a great place to start because, in addition to helping identify occupants who have been exposed to biotoxins such as mold, it is free and takes just 15 minutes!

The VCS Test works by measuring one of the neurologic functions of vision called contrast.  Contrast sensitivity can be affected by exposure to biotoxins (such as mold and bacteria-produced toxins), nutritional deficiencies, VOCs, parasites, and bug and insect stings/bites.


 VCS Test ProsVCS Test Cons
  • This vision test is completely free and can be taken in just 15 minutes from the comfort of your own (well-lit) home
  • Results seem to reliabily correlate to biotoxin exposure
  • All members of the family can be tested, as biotoxins tend to affect all individuals differently
  • Because the VCS test does not tell you the exact biotoxin that you are being exposed to, a positive result does not necessarily indicate the presence of mold.  In fact, biotoxin illness may be caused to bacterial biotoxins, and be completely unrelated to mold or mold toxins.


DIY Tape Sampling

If you have visible mold in your home and you would like to know if it is dangerous or not, I typically suggest DIY tape sampling.  With this testing procedure, you take tape samples of suspected mold, send them off for identification under a microscope, then receive a digital report of the types of mold present in your home.

This test provides peace of mind about whether the mold in your home is toxic or benign.

All in about 4 weeks and for around $50! If you are interested in doing your own tape mold sampling, I would like to invite you to check out my healthy home discount group, where you can get a FREE tape sampling kit with the purchase of 8 tape samples.


 Tape Sampling ProsTape Sampling Cons
  • You can save a lot of money by taking your own samples, rather than hire an environmental consultant to take them for you
  • Identification is done by microscopy, and you are given digital images of the microscopic mold spores on your own stuff
  • Sampling method is very focused – rather than testing ALL of the dust or air, you can take a sample just from a sofa, book, or bathroom vanity.
  • For the ~20% of the population who cannot properly detox from mold and mycotoxins, taking tape samples may be harmful to health
  • Certain locations (such as behind drywall and underneath vinyl flooring) are difficult to access for tape testing


Blood Tests

If you are being affected by biotoxins (the toxic by products of things like molds and bacteria), your blood may give the best clues about the extent of the damage.  This is a great option, but may cost more than the previous suggested tests.

According to Dr. Ritchie Shoemaker, the following can be useful blood tests for diagnosing biotoxin illness:

  • VIP – Vasoactive Intestinal Polypeptide (Normal Range: 23-63 pg/mL)
  • MSH – Melanocyte Stimulating Hormone (Normal Range: 35-81 pg/mL)
  • TGF Beta-1 – Transforming Growth Factor Beta-1 (Normal Range: <2380 pg/ml)
  • C4a (Normal Range: 0-2830 ng/ml)
  • AGA IgA/IgG (Normal Range: 0-19)
  • ACTH/Cortisol (Normal Range: ACTH – 8-37 pg/mL; Cortisol – a.m. 4.3-22.4 / p.m. 3.1-16.7 ug/dL)
  • VEGF (Normal Range: 31-86 pg/mL)
  • ACLA IgA/IgG/IgM (Normal Range: IgA – 0-12; IgG 0-10; IgM 0-9)
  • ADH/Osmolality (Normal Range: ADH – 1.0-13.3 pg/ml; Osmolality – 280-300 mosmol)
  • MMP-9 (Normal Range: 85-332 ng/mL)
  • Leptin (Normal Range: Male: 0.5-13.8 ng/mL; Female: 1.1-27.5 ng/mL)


 Blood Testing ProsBlood Testing Cons
  • This method is highly accurate, and specific to every individual in the affected building
  • Blood draw can be completed in as little as 5 minutes (I did my last one with a sleeping toddler draped over the other arm #momlife)
  • Levels can be monitored over time to see if remediation efforts are effective
  • Many doctors are unaware of the dangers of biotoxin illness and will be unfamiliar with the necessity of these types of tests.  You may need to call around and shop for a doctor – I promise it’s worth it!!
  • Cost may be an issue, depending on if your tests can be covered by insurance


HERTSMI-2 Scoring System

HERTSMI-2 is a scoring system developed by Dr. Ritchie Shoemaker which is applied to the DNA ERMI test results.  According to Dr. Shoemaker, “This scoring system is application of the DNA testing shown on ERMI test results. The new roster is designed to help patients (previously sickened by water-damaged buildings) understand if a given building is safe for occupancy.”

HERTSMI-2 essentially alerts occupants to the presence of 5 particularly dangerous mold species: Aspergillus penicilloides, Aspergillus versicolor, Chaetomium globosum, Stachybotrys chartarum, and Wallemia sebi.


 HERTSMI-2 Scoring ProsHERTSMI-2 Scoring Cons
  • Helps patients who have been previously sickened in a water-damaged building known if a given building will be safe for occupancy
  • Unlike ERMI testing alone, the HERTSMI-2 scoring system provides context, giving occupants peace of mind about the safety of their home environment
  • Test is not yet in widespread use and there is not a lot of scientific data about the results
  • HERTSMI-2 should not be used to determine whether a building is unsafe in general, but may be very useful in evaluating potential residences for sensitive individuals


Environmental Relative Moldiness Index (ERMI) Test

Environmental Relative Moldiness Index (ERMI) testing has long been touted as the gold standard among mold professionals, but certainly has
its limitations. In fact, the creators of the ERMI test, the Environmental Protection Agency (EPA), says the ERMI test is a “research tool” which should not be used for home mold testing.  Did you catch that?

The ERMI test uses a small vacuum to take carpet dust samples.  Samples are then sent to a microbial laboratory (EnviroBiomics and Mycometrics are two of the most recommended) where proteins in the dust are tested for the genetic presence of 36 mold species.

I’m not say that ERMI testing has no value, just providing a balanced look at the limitations of this highly-lauded mold test.

  • Occupants can save money by doing their own ERMI testing
  • Moderately priced, with testing and results costing just a few hundred dollars
  • Testing can miss extensive hidden toxic mold entirely, providing a false negative result
  • Does not test for mycotoxins or mVOCs, only for spores themselves



I think the best place to start with mold laboratory testing is with the CAP DNA test, created by Dr. Joe Spurgeon, which tests for three dominant fungi species (Cladosporium, Aureobasidium, and Penicillium). Compared to ERMI, CAP testing is less expensive and more useful in determining human health implications because it is based on fungal concentrations (mold levels).


 CAP DNA Testing ProsCAP DNA Testing Cons
  • Unlike ERMI testing alone, the CAP scoring system provides context, giving occupants peace of mind about the safety of their home environment
  • Does a great job of indicating the presence of mold, and giving a quantitative overview of the problem
  • Although this test identifies 3 of the most common fungal species, they are not necessarily the most dangerous.  The results of CAP DNA give you more of a quantitative view of the mold problem, while something like HERTSMI-2 gives you more of an indication of how dangerous your mold is.  For example, CAP DNA would not indicate the presence of the dangerous Aspergillus mold, which can easily become airborne and infect lung tissue.
  • Test is not yet in widespread use and should not be used to determine whether a building is unsafe to occupy



According to Dr. Ritchie Shoemaker, “A common concern for those who are trying to understand cognitive problems in moldy patients is to answer how is it that inflammation in the body is inflammation in the brain. The blood brain barrier, as it is called, results from additional “tight junction features” between cells that line blood vessels. These tight junctions are loosened by particular inflammatory processes including TGF beta-1 and IL-1B. These two compounds are well shown to be significantly elevated in patients with systemic inflammatory response syndromes acquired following exposure to the interior environment of water-damaged buildings.

The computer program called NeuroQuant has been used in the traumatic brain injury field for some years. This unique and sophisticated program can take a properly run MRI of the brain and assess volumes of 15 different brain areas. To my knowledge, no one had used NQ to assess brain injury in patients with mold illness before.”


 NeuroQuant ProsNeuroQuant Cons
  • Highly specific results based on how your brain reacts to the biotoxins present in water-damaged buildings
  • “These preliminary data are being verified and expanded, but the longstanding tenuous argument against the link of exposure to water-damaged buildings leading to development of adverse cognitive effects appears to be ready to disappear under a blizzard of hard data. ” – Dr. Shoemaker
  • Unless brain imaging is covered under your insurance, may be a significant cost associated with this type of mold testing
  • This is still cutting-edge science; Although the technology has been in use for brain injury, it has never been studied for use in mold-related brain injury


Air Sampling


According to the website, Paradigm Change, “The main problem with air testing is that since it is looking only for whole spores that are floating in the air rather than at genetic material, it tends to miss certain species of mold.

For instance, perhaps the most problematic species of mold, Stachybotrys, is released from colonies into the air in waves.  Stachy also makes a heavy, sticky spore that falls rapidly to the floor and then usually breaks up into spore fragments, which are at least as toxic and dangerous as the whole spores.

These spore fragments mix with the other dust in the environment and get blown or carried all around the building.  As a result, Stachybotrys almost never shows up on air tests even when it is a major problem. Certain other molds may not come up either.”

 Air Sampling ProsAir Sampling Cons
  • May be helpful when allergies and asthma are the primary concerns
  • They must be conducted by a professional mold inspector and tend to be fairly pricey, often at least $1,000
  • Air testing looks for entire spores rather than fragments or DNA so it tends to miss certain species of mold (for example, air sampling usually won’t catch dangerous “black mold” aka Stachybotrys)


8 Healthy Home Tests

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What About Mold Remediation?

How to Prevent Mold at Home

Once you have a professional remediation (or if you were lucky enough to find no signs of mold) – you want to keep your home mold-free.  So how do you do it?  I created a free printable mold avoidance checklist (perfect for a healthy home binder!) which walks you through the easy ways to prevent mold growth in your house.


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25 Ways to Protect Your Home From Toxic Mold

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Have you ever run any of these tests?  I’d love to hear about your experience with mold testing!