How Can I Check My House for Mold? | How Can I Clean Mold?


A year or so ago, I was in an unfinished basement putting down a vapor barrier (that black plastic stuff). While I was down there, I saw more black mold than I’d care to see ever again.

It was literally all over the place.

A few months later, I was in my own bathroom, scrubbing away at the mold that had accumulated.

(No, this is not the mold that I had in my house!)

Suffice to say, I learned the hard way that there’s mold everywhere. It can grow in places you go every day and in places that you never check.

Which leads me to the question “how can I check my home for mold?” I mean, if it can grow all over, then how could I possibly check for it? Well, I’ve got some good news for you.

Most molds are easy to spot, provided you know where to look. It can grow on walls, ceilings, in tucked-away areas, anywhere. If you find a spot that you think is mold, get some diluted bleach and a Q-tip and apply a little bit to the area. If it lightens up fast or comes back after a while, then assume it’s mold.

Now, before you ask, the dilution that you should have your bleach at is somewhere between 1 part bleach for 10 parts water and 1 part bleach for 20 parts water. You should shoot for a pretty good dilution. After all, you don’t want to permanently bleach the surface you’re checking!

You will also want to make a pretty minimal batch of your dilution, there’s no need to waste any bleach today. So long as you’re just testing one spot, you won’t need a lot.

What Does Mold Look Like?

Most household molds usually look like black spots, blotches, and smears. Mildew is the most common type of mold that you’ll see in your home and usually shows up in the corners of your bathroom (in your shower, by your sink, in dark corners).

Of course, mold can accumulate in other parts of your home as well, but I’ve seen that most people get mold in their bathrooms, basements, garages, and other rooms that commonly get wet. If the mold is anywhere else in your home, then I would worry that you might have a severe mold issue.

For the untrained eye, mildew and mold are usually hard to distinguish from just a dirty spot on the floor, ceiling, or walls of your home. It might just look to you like you need to do a better job cleaning the next time you get around to it.

That’s where the little test that I mentioned above comes into play.

If you’ve cleaned a spot a few times before, or if this is your first time getting around to it and you think it might be mold, then here’s how you test if it’s mold with ease.

  1. Gague about how large of an area the possible mold spot is.
    If the area in question is tiny, then be sure to mark it in some way so you know where it is so you can check on it later. (To see if it returns.)
  2. Prepare your bleach dilution.
    Again, this should be between 10 parts water for every 1 part bleach, to 20 parts water for every one part bleach. Ideally, shoot for 15 to 1, but you’ve got some wiggle room. Don’t stress too much.
  3. Apply your diluted bleach to the area in question.
    Use a Q-tip (or cotton swab, if you want to be fancy) and wet it with the bleach dilution. Apply it directly to the spot in question. Don’t scrub on it.
  4. Wait.
    Give it a few minutes. Your bleach needs to react with the mold. Once you’ve waited, check to see if the spot that you put the bleach on got any lighter. If it did, then it’s most likely mold. If it remains dark, then it’s probably just dirt.
  5. Wash!
    If it’s dirt, you can just wash the dirt right on off. However, if it’s mold, then that complicates matters.
    If it is mold, then you have a few courses of action–read on and I’ll share them with you a little further on.

Where Should I Check for Mold in My Home?

If you are checking your home for mold, then you should try to check every possible nook and cranny. As I see it, the best amount of mold in your home is no mold.

When checking your house for mold, start in your bathroom. Check around your toilet, sink, and shower. Mold–mildew in particular–likes to start growing in grout and in whatever crack it can find. Also be sure to check your garage, basement/crawlspace, and attic for mold. Anywhere where moisture is present can be a place for mold to start growing.

The humidity in your bathroom makes it the prime spot for mold to start, so I’d personally spend a lot of time there searching for any signs of mold. Once I’ve done that, I would walk around my home’s exterior and look for any signs of mold. Once that was done, I’d check the basement, which is always wet and dark. You’ll be looking for dark patches or other odd-colored patches on your walls, floor, or ceiling. Finally, check all the rooms in your home, including your garage.

When you’re checking all of these spots, be sure to check the corners of the rooms, behind cupboards, inside of them, and beneath your sinks. Mold can pop up anywhere, but it especially likes dark areas that stay wet.

How Do I Clean Mold Once I Find it?

If you’re like me and you find out that you’ve got mold, then odds are you want to get rid of it. If not, then let me warn you that living with mold is not healthy. I’ll let you do the research to figure out why, because I don’t want to go off on another tangent.

Now, there are a couple of ways to get rid of mold, every way will take a good amount of time (a couple of hours or more, if the area that’s affected by mold is larger than just a few square foot or two). Some methods are better than others, but I prefer the EPA’s way of doing things over the other ways out there. I’ve done it and found it super easy.

Before I dive in, though, I must say that you will have to check to see why the mold started. You could have leaks, and those will have to be fixed. If it’s in your bathroom, then there’s a chance that you need to improve your bathroom fan. A dehumidifier could help as well.

Step By Step Guide for Removing Mold

Here are the steps to clean mold in your home. These steps apply to hard surfaces like your walls, floors, and ceilings. If you’re dealing with a soft surface or untreated wood, then you’ll have to Google the best way to clean those surfaces. In the steps below, I have links to all the gear you’ll need.

  1. Put on some protective gear.
    Wear safety glasses (trust me, you need them, I learned the hard way).*
    Wear rubber gloves.
    Wear pants and long sleeved shirt.
    Wear closed toe shoes.
    Wear a mask
  2. Grab the supplies you’ll need.
    Get a water bucket.
    Get a rag towel (or a few) to scrub with.
    Get your detergent. (I found Finish Power Powder worked the best since it was abrasive.)
    Get a step stool if needed.
    Get a big towel (probably a few) to completely dry things off.
    Get some garbage bags.
  3. Mix your detergent with water in the bucket.
    I did a 3 part detergent to 15 part water mix with 1 part bleach when I was cleaning my mold. I used the bleach to ensure that the walls were totally clean when I was done and this is something the EPA doesn’t recommend, but other sites do. I thought the bleach and I had a whole lot of luck with my mixture with the bleach and deterget, just using detergent didn’t do much for me.**
  4. Set up everything near the mold and be ready to stay there until you are done.
    I say this because you don’t want to track whatever you’re using to clean your walls with through your home. If you use bleach and detergent, like I did then that bleach could ruin your carpet. Don’t do that to yourself.
    If you live with kids or anyone else, you might want to cordone off the area where you’re working so they don’t walk through it.
  5. Start cleaning!
    You’ll have to scrub for a long while on some spots, especially if you let the mold or mildew take hold and grow for a while.
    I kept a small bowl of my powdered detergent on hand as I cleaned and I dabbed my wet towel in it to use as an abrasive when I got to really hard to clean spots. It worked like a charm. Be careful to not scrub too hard if you’re doing this on a porous material.
    Scrub down all the areas affected by mold and try to clean the area immediately around it as well.
    Once you finish, give the area a once over and make sure you got everything. It’s a pain to set all of this up, so make sure you’ve got it all!
  6. Dry everything.
    Dry everything and dry it completely. Do not skimp on drying!
    Make sure you got every single drip. When I did my bathroom, I left a few drips and had some ugly, dark stains on my walls until I cleaned them off.
  7. Pack it away.
    Now that everything is dry, it’s time to clean up. Wash your clothes on hot in your laundry machine and either dispose of your towels and rags in the optional garbage bags (immediately take them outside) or wash them on hot as well. If your laundry machine is like mine, I recommend setting it on “Sanitize”.
    Throw away your mask, wash your gloves thoroghly or throw them away, same with your safety glasses. Wash your stool and bucket well.
  8. Final teps (optional)
    Now that you’ve cleaned your affected area, you can repaint it, should you so please. I painted over my walls with Killz (which kills mold and makes sure it doesn’t come back). Once that dried, I went over it again with my desired wall color with a waterproof paint.

Now, I know that’s a ton of stuff to remember, so I made a PDF (and a JPEG/JPG) that you can download and print off to use for reference. You can download my mold cleanup checklist below.

*Now, I really mean it about the protective gear that I recommended. Especially the safety glasses. I got a little wild when I was scrubbing down the walls of my bathroom and got a chunk of the detergent in my eye. That was zero fun. Don’t make the same mistakes I did!

**Bleach isn’t fun to play with, that’s why we have all the safety equipment I listed. I got some burns from the bleach I used (I wasn’t careful enough and I didn’t wear any protective gear). Don’t make the same mistakes I did. Having burns on your feet from bleach is not fun.

What Should I Do After I Clean the Mold in My Home?

Once you’ve put in all the time to clean the mold (of even if you haven’t had to ever clean before), then it’s probably time to think about what you can do for prevention. No one likes spending hours and hours cleaning something, so all the prevention you can do now will save you that time.

So, what can you do to prevent mold?

Well, once you’ve taken care of your mold, the biggest threat is gone. Congratulations, you’ve stopped the mold from spreading for now.

Alas, that victory might not be permanent.

If your mold came because of a leaky roof, pipe, or something else, then the problem will return. You should deal with that as soon as possible (preferably before you spend your time cleaning because that sort of issue oftentimes results in walls, floors, and ceilings being torn up).

If you don’t have a leak that was causing the mold, then odds are that you’re facing a humidity issue.

So, how do you fix humidity? How can you even know what your home’s humidity is?

Well, I’ve got amazing news for you. There are devices out there that can gague the humidity levels in your home! The best ones out there can even tell you if you have a mold risk. AirThings, for example, has one of these humidity sensors that can warn you before the mold can take over.

If you’d like to get the AirThings sensor to monitor the humidity in your home, you can order it directly from the manufacturer here. You can use the code ape10-10off to get an additional 10% off the price too!

Now, if you know that you have an humidity problem, then you can purchase something called a dehumidifier. These machines pull the moisture out of the air, thereby reducing the humidity in your home. By pulling out moisture, you are able to lessen your risk of having mold take over.

If you’d like to learn more about dehumidifiers, then I’ve got a ton of information for you to check out! Here are just a few of the articles I have on dehumidifiers.

How Do I Know if I Need a Dehumidifier or a Humidifier? | What’s the Right Humidity for My Home?

My Aiho Dehumidifier | What I Love About this Dehumidifier and What Makes it the Best

Top Five Affordable Air Purifier Dehumidifier Combination Units | What is the Best Air Purifier I Can Buy?

What is the Best Basement Dehumidifier?

What Are Air Purifiers with Dehumidifiers?

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Jonathon Silva

Jonathan Silva is our longtime Air Purifier Essentials author. He has been writing on air purification technologies for his entire professional career.

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