First, if you see mold then there is simply no point in testing. Mold has to get removed regardless of what kind it is because ALL mold is a danger both to your health and structurally. True not all mold releases mycotoxins (the dangerous substance released by the overly scary black mold!), but all mold is an allergen simply because it is a foreign substance in your body. Some people are more susceptible to it then others but all of it is potentially harmful. Additionally, mold causes damage to the surface it’s on and can be as minor as surface staining or as major as structural damage.
The above paragraph is the official answer to mold testing. However, I’m going to let you in on a little secret that will make every mold remediation company cringe. If you see minor mold, meaning a few spots here and there, in an area that has had minor water intrusion it is worth getting a mold test complete to see if it is something you can fix. My personal (not professional) rule of thumb here is if there’s a minor amount then get a mold test and see if it’s toxic mold and needs chemical remediation by a professional removal company. If it tests as non toxic mold that is simply an allergen then a solution of bleach and removing the moisture can do wonders to save your budget. In this particular instance a $375 mold test can you save $2000 on remediation for something you can do yourself.
A mold test should be performed after the remediation process to ensure it is removed. Be wary of contractors that don't disclose this in the initial estimate because they will tack it on at the end as a hidden fee. When this happens two tests should be done, so don't get screwed paying for a bunch of services you don't need.
The two tests that must be done are an indoor air sample of the area with the remediation. So if you had mold in the bathroom get an air sample at or near that area not in the garage. The second sample that should be taken is an outdoor air sample as a control. This sample is taken to determine if the mold in the air is higher then that of the natural environment. Without this test you have nothing to compare it to so you will never know if it is high or low.
Some testing companies (yours truly) can be overly cautious and recommend 3 or 4 tests when you could get away with 2 or 3. I had a client just the other day that needed a mold test in the crawl space, but because the duct work was poorly installed I recommended one in the house as well. The client asked if she could do just the crawlspace. The simple answer here is yes you can but should you? the risk is really yours and my legal/professional recommendation is get 3.
Next on the list, walk in to your basement and see if it smells damp or musty. If it does there is a HIGH probability you have mold. Get it tested now before you have to pay thousands of dollars in the future to fix structural damage. If you have mold you can pay a relatively inexpensive price for a built in dehumidifier with a discharge pump and be done worrying about it.
On this same note if you smell mold (which has a very distinct oder) you need to have it tested. Your next question is why would I need to test it if I smell it? Doesn't that mean I have it? Absolutely you have it but in this case it still needs testing. You need to determine the degree of mold spores in the air. This will give a person trained in reviewing lab results an idea of the best remediation process. Basically if you smell mold you could have very minor mold that can be cured with the dehumidifier, or major mold and structural damage hidden and the ratio of mold in the air can give the tester an idea as to which. The other reason behind the test here is to know if it’s toxic so the remediation process can prioritize the steps to fix it. Bottom line here if it’s non toxic surface mold dry it out and cleaning it could be the $1000 fix for the problem; if it’s toxic mold it may need to be dried and chemically treated for $3000.
What about water damage? If you have a roof leak, a plumbing leak, HVAC condensation on the ducts, etc. Then you need a mold test provided 1 condition is met. Though mold can start growing immediately after water is introduced it isn't realistic to think that you would test high for mold because a water leak hit and was dried immediately.
A good rule of thumb here is if the water has been present more then 48 hours, or if you do not know the amount of time it has been going on then it is worth testing. Especially if you have a smell of mold in the air! First step address the leak and let it dry, 2nd step get an air sample taken to determine if you have mold present!
After mold remediation work has been complete an air sample should always be taken to determine if the counts have returned to normal. If the mold remediation was done properly this should be able to be complete within 24 hours. Unless you personally know and trust the contractor doing the work then hire a 3rd party inspector to check the house. As a quick tip the inspector should inspect the work completed before taking his mold sample, and that should be included in the price. Mold tests are expensive don't let a lazy inspector spend 5 minutes taking a sample only to walk away with your hard earned cash. A good inspector will check the work and verify visually that no mold is present, if it is he will schedule a re-inspection with you. Still an added fee since you have to pay him/her a $100 re-inspection fee but better then paying for a mold test to be done again. If it requires another inspection due to poor or unfinished work make the contractor pay the difference.
Sick, elderly or adolescence at home create strain on the family and their weakened immune system is not hardy enough to handle mold as a simple allergen in the air. If they are displaying symptoms of allergies then see a physician, though no mold expert should ever overrule the doctors advice, but it’s worth having the mold in your house tested so you can show the doctor the results and see if that better helps them determine a cause.
When you purchase a new home especially one with a basement or evidence of water damage it will justify the price in the long run. Most houses I inspect turn up negative, but the ones that test positive are always thankful they paid the money to do the test because the seller then pays for the mold remediation. A standard mold test is about $375 give or take depending on the number of samples to be taken, which is a bargain when looking at $10,000 worth of damage and repairs.
What about for renters? Before I was an inspector and a home owner I lived in a shanty 1 bedroom apartment. The ceiling had so much mold on it the tiles would cave in as I was lounging around my hovel. Had I known better at the time I would have had a mold test performed so that I would have documentation to prove that the apartment did not uphold their end of the lease (or the law since most states have language written to protect the tenant from health issues). This would have got me out of my lease without paying the $2000 early termination (extortion) fee, when it was time to leave. On that same note, and this is something relatively no one does but is a good idea if you can afford it, but getting a home inspection when you move in to a rental, can secure your deposit when it comes time to move out. If you’re planning on buying after your lease is up you could even get a discount by signing an agreement that the same inspector will do your house when you purchase.
People are always afraid to ask for things like that but as soon as you get over that fear you can start saving yourself money. Any inspector would jump on that since it guarantees them business in the future. I know I would even if it meant I did this inspection for a price to only cover my costs.
Bottom line here is landlords can screw you and bad ones will every time. Get the documentation in hand before it comes time.
Water damage can do some funny things; efflorescence, dirt, grime, algae, and even blown in insulation can all look like mold. That’s part of the reason why in certain circumstance it does make sense to test when it is visible. 9 times out of 10 the inspector will be able to tell the difference but sometimes when substances mix, for example when efflorescence and wet dirt get stuck to a wall, it can make it nearly impossible to tell visually.
The bottom line here is that you should not waste money on a mold test when it’s not needed. I don't recommend a mold test on every house I inspect and if an inspector is telling you that you need one, make sure it falls in one of these categories or get a second opinion. I often get new clients because someone called wanting a second opinion, some inspectors charge for a consult others don’t it really just depends. I never do as long as the person is in a geographic area that I service, or the consult is not overly time consuming. However, when a mold test is needed you should do it as quickly as you possibly can, before you cause more issues both structurally and to the residents. As a veteran I use a lot of military analogies so let me leave you with one; mold is devastating if left unchecked and I used to tell my Soldiers “when it’s time to strike, hit as fast as you can, as hard as you can, and be the first one to lay the hammer.”
I am a United States Army Veteran with over 10 years construction experience prior to my service. After my time in the military I enrolled in InterNACHI's rigorous course work to become a certified member and prepare for the National Home Inspectors Exam. I continue to push inspection courses and education, attaining and exceeding the required continuing education courses