Home Cleaning Tips Reader Q & A: I Can’t Get Rid of The Mold in My Bathroom, Should I Be Concerned For My Health?

Reader Q & A: I Can’t Get Rid of The Mold in My Bathroom, Should I Be Concerned For My Health?

by Catherine

Bathroom Mold:

Harmless and Inevitable VS. Atypical and Worth Investigation

Mold in the bathroom is as anticipated as food in the kitchen, right? I mean, most people do not expect to find one without the other? And, although bathroom mold is unsightly and annoying, there aren’t any real health issues to worry about with it, right? Well, the answer to that question is, unfortunately, not so simple, because it depends. It depends on where that mold is growing, why it is growing, and whether or not you have any other additional water, environmental or ventilation issues going on in that bathroom.

I do want to back up a little, though, to first state that I actually think that you CAN and SHOULD expect to be able to keep “typical” bathroom mold at bay. By typical, I mean the discoloration that can occur around and between tiles and on grout, and sometimes inside your toilet from the water line when it is not flushed often. The truth is, though, that in a healthy home, “typical” mold should not plague you constantly. In fact, when you can’t control the amount or occurrence in frequency of the growth of this mold, and you find yourself constantly cleaning and scrubbing to get rid of mold in the same spots, it might be an indication that you need to dig a little deeper or to look closer at why the environment inside your bathroom is so hospitable for mold in the first place. This is because, at the end of the day, the visible presence of mold points out the presence of mold spores, an avid water source, and organic material for those spores to settle, grow, and spread on. In addition, anywhere there are mold spores and water, a larger mold infestation could take place if the conditions aren’t controlled and monitored. Thus, knowing what to do to control “typical” bathroom mold and knowing what to look for as far as larger issues could help you to catch and prevent a larger problem.

I actually didn’t come up with this topic on my own, even though I have spent countless hours honing my skills and product selection on how to best clean my bathroom and keep mold at bay. (I’m hoping you don’t actually think that all I do is clean and think about mold–well, it is a LOT of what I do, but not my whole life.) Anyway, the impetus for this topic actually came from an email that I received:

Dear Catherine,

I have been reading your blog for quite some time now and have found it incredibly helpful and supportive. I am actually writing today with a question that, in a way, feels a little trivial in the scheme of things, but that I really want to solve—maybe it’s because I am a little obsessed with mold at this point and with making sure I am not being exposed. I guess a little background on me would be helpful first:

I was diagnosed with CIRS two years ago after living in a very water-damaged and very moldy apartment complex. (Note: CIRS is the anacronym for the chronic inflammatory response initiated and perpetuated by the immune system when the body begins to react to defend itself from biotoxin exposure. Indoor molds are one of the offending biotoxins that cause this immune response in some genetically susceptible people. Because the exposures are often gradual and over long periods of time, the diagnosis is usually made by reported and clinical symptoms and lab diagnostics that show multi-system inflammation. It has been estimated that about 25% of the population have the gene for this type of biotoxin-triggered inflammatory illness.)  I have since moved into a healthy, “mold-free” home. I had lots of help finding it and used an environmental inspector and did lots of testing before moving in. There was no evidence or reporting of previous water damage and the ERMI score was good. (Note: ERMI stands for Environmental Relative Moldiness Index. It is a scoring system that was devised by the Environmental Protection Agency in order to determine healthy vs. unhealthy mold levels for indoor air. You collect dust samples via Swiffer cloth or vacuum cannister and that dust is analyzed and scored for specific molds. The score gives the indoor environment a rating to show whether or not it is “healthy” from a mold standpoint.) I see a functional medicine doctor as well and all of my labs and symptoms are finally stabilizing.

My question has to do with the bathroom—it seems that no matter what I do, we have reoccurring mold and mildew growth on the grout around the tub, as well as reoccurring mold on the shower curtain liner. To give you an idea, I have been living here now for 6 months and have replaced the shower curtain 2 times already! The bathroom is well ventilated and we run the fan for at least 30 minutes after each shower. Should I be concerned about this mold? What are your recommendations for getting rid of it? If I spend a lot of time in or around the bathroom, I don’t feel as well, so I am getting concerned. Any insight you can offer is appreciated.


Here is my reply:

I am happy to hear that you are being so proactive and took precautions with testing before you rented and with getting out of the mold exposure to better your health. I am also happy to hear that you used an environmental inspector. That is a great way to get a “relative mold baseline” and to help with continually monitoring to see if and when anything changes as far as mold is concerned. A quick personal note on the ERMI before I answer your question, though: It is a great tool, although not a perfect tool, for people who know that they are mold sensitive. The caveat that I have for it is that its accuracy for determining the health of a home is very much based upon where and how the dust was collected, and whether or not it was paired with any other inspections. It is also my growing opinion as I speak with and connect with chronically ill people and the environmental professionals who work with this population that the ERMI is a little too lenient in its allowable numbers. This means that the ERMI allows as “safe,” some environmental mold levels that are actually quite inflammatory to some CIRS patients. This is not meant to scare you or to make you question anything you have done thus far. In fact, your use of an environmental professional during the process actually lends validation to your testing results. I just wanted to point that out before giving you any advice, so that you will listen to your body and dig deeper into your environment, especially since you notice that you are not feeling well in and around that bathroom area. You may even want to revisit that ERMI with the inspector and go over what, if any, molds were found, and at what levels. Just going back and analyzing that data may bring you some answers that you didn’t think about before.

Really quickly, I also need to point out a distinction between mold and mildew.

Mildew is a surface fungi that can easily be identified as a patch of gray or even white fungus that is lying on the surface of a moist area. Mildew is easily treated with a store bought cleaner and a scrubbing brush. It is difficult to see in a bathroom, but does have a musty smell. Most people plagued with bathroom fungus are actually talking about mold, because it is what they see.

Mold, on the other hand, can be black or green and is often the result of a much larger infestation. This type of fungus can appear on almost any surface or material if their is a water source.

Back to your actual question:

The short answer is, “No,” bathroom mold on grout is not something you need to be overly concerned about, nor is mold on a shower curtain. The bathroom is sort of a home’s “water room,” so some microbial growth is to be expected. But, because you seem to be having issues with getting that mold to stay away and are feeling your CIRS symptoms crop up in around the bathroom, it is necessary to not just dismiss the mold as a possible contributor. Thus, I am going to walk you through some steps that might help.

Let’s start with some bathroom science and easy solutions first–easy solutions are ALWAYS best, especially since this is a rental property and you will want to minimize the money you spend on it. Then, if those don’t seem to solve the problem, I will give you some advice on how I would proceed with some testing and further investigation.

Bathroom Humidity

Bathrooms are areas that, by nature, are prone to conditions of high relative humidity (RH). Thus, to lessen the potential for mold growth, you have to do things to minimize the moisture. In a bathroom, this is difficult, but can be done. It sounds like you are already employing my first tip, which is to run the exhaust fan both during your showers and for 30 minutes after you are finished showering. This will ensure that the steam from the shower is being readily sucked from the room and expelled outside where it can dissipate and not linger to raise your indoor humidity and foster mold growth. Addressing the humidity levels alone will prevent mildew from reoccurring as long as there isn’t an additional moisture problem. Here are some important things to remember with bathroom exhaust fans and with RH in bathrooms:

  1. Bath fans should ALWAYS be vented to the outdoors. Bath vans should NEVER terminate in a wall cavity, attic, basement, or garage. If you find that this is the case, since you are in a rental situation, you are better off not using the fan and opening a window during showers, or purchasing a fan to sit on the countertop for ventilation and a portable dehumidifier to run to suck the moisture out of the room during and after showers.
  2. The bathroom fan needs to be adequately sized for the space. You can read my detailed post about that HERE. If the fan is not powerful enough, it will not be able to remove the humidity efficiently. (Note: To get an idea of if your fan moves the air sufficiently, allow your bathroom mirror to steam up. Then, turn on the fan. The mirror should clear in 7 minutes or less.) A low-cost fix for this would be to purchase a countertop fan to also run in the bathroom during showers. It would help to increase air flow and the drying out of the bathroom post shower. I am honestly of the mindset that you can never have too much help with taking care of the humidity, so if you are extra keen, a portable dehumidifier that you empty daily wouldn’t be a bad idea for this scenario either.
  3. Just because you hear your fan, doesn’t mean it is working. Do the “toilet paper test” to make sure that the fan is actually sucking the air. This entails placing a small square of toilet paper on the exterior of the fan while it is on to make sure that it sucks and holds onto the toilet paper.
    It can eventually float to the ground, but it should be drawn up and against the fan cover. If the fan fails the test, you need to ask you landlord to replace the fan with one that is functional. There are other reasons why it may not be sucking with lots of strength, but since this is a rental, those are sometimes expensive fixes. We just want it functional.
  4. Bathroom fans need to be kept clean and free of debris and clogs, so they can actually do their job. Bath fans are notoriously filthy and not cleaned or maintained. Simply allowing too much dust (dust from the outside—by nature of the fan being on, it is exchanging indoor air with outside air, from lint, from skin, from toilet paper, etc.) to collect on the vent cover and inside the fan can be food for mold growth. This mold growth alone could be causing you to feel sick in there. Cleaning the fan thoroughly, and keeping it clean will improve its air movement capacity and will improve the air quality in your bathroom. Read my post on cleaning your bathroom fan HERE.

Once you tackle the fan maintenance and make sure that is sorted and working properly, it should be taking care of the immediate humidity issue rather adeptly. This alone should help to control the mold/mildew from coming back once you clean properly—especially on the shower curtain.

Cleaning Mold Off of Tile and Grout

The best and least toxic way to clean mold from grout and tile is by using hot water, castile soap (the soap must not have detergents, so that it doesn’t leave a residue for mold to grow on) and Borax. Oh, and some elbow grease. You do not have to use toxic cleaners and chemicals to sanitize! You also should NOT use bleach. (HERE is my post on why I stay away from it.)

Here is the method that I use to clean our tubs, showers, and grout:

  1. Remove all bottles and toiletries from the tub shelves and from around the shower. You need a clutter-free area to work.
  2. Wet the bottom of the tub and add a small amount of castile soap—I love Dr. Bronner’s Sal Suds for this.
  3. Sprinkle a small layer of Borax over the bottom of the tub. This creates a pumice.
  4. Wet a sponge or scrub brush and use the Borax/soap pumice to clean the tub, the tile and the grout and fixtures around the tub.
  5. Intermittently, use hot water to rinse and repeat until the tub, grout and tile are clean.
  6. For stubborn mildew stains, you can use hydrogen peroxide. I dip an old toothbrush directly into the cleaning peroxide and apply it to the stained areas. It may take a little scrubbing to remove the stains.
  7. Rinse the areas with hot water.
  8. When you have completed cleaning and all soap is rinsed clean, mist the grout, tile and walls with EC3 Mold Spray. Allow it to air dry. This will work to prevent mold from coming back.

Cleaning Shower Curtains

First, since I do not know what type of shower curtain you have, I will say that I prefer the fabric curtains that are non-toxic and washable over the plastic ones.

The plastic ones do not dry out as quickly, they tend to off-gas terribly, and they cannot be washed in a washing machine. Thus, my instructions are going to be for the fabric curtains only. If you have a plastic one, I would replace it when you can. Also, before I get into cleaning it, make sure that after each shower, the curtain is drawn closed and hangs without bunches or pleats, so that it can fully dry out between showers. The trapped moisture will work against you and will also hold additional humidity in the room.

To clean:

  1. Mist whole curtain while hanging in tub with EC3 Mold Spray, concentrating on the bottom part where most mold and mildew form. Make sure it is fully spread out and not bunched together.
  2. Remove the curtain from the tub.
  3. Wash it in your washing machine by itself on the hottest setting. Before starting the cycle, add a mild, non-scented detergent—my favorite is Dr. Bronner’s Sal Suds, ½ cup of Borax, and 2 ounces of EC3 Laundry Additive.
  4. When cycle is complete, toss shower curtain into your dryer on delicate or rehang it in the bathroom and allow it to air dry with the bathroom fan on.

All of the mold and mildew stains should be gone. If you have a stubborn one, you can do the method outlined above, but soak the curtain in the wash basin after the machine agitates for 10 minutes to 1 hour. You can also keep a bottle of EC3 Mold Spray in the bathroom and use it to periodically spray the curtain down after showering. This will both decrease mold spore counts in the bathroom and prevent mold from forming on the curtain in the future. I actually remove and wash our shower curtain as part of my mold maintenance routine about every 2 months.

What If I Clean and the Mold Comes Right Back?

If you follow those steps, the mold comes right back, and you continue to feel bad, then, you need to put your detective hat on. The first thing I would do would be to revisit all of my humidity control advice above. Make sure you are employing all of those tactics and doing everything you can to get the RH down in the bathroom and to keep it down. If I wasn’t clear before, I’ll say it here again, humidity control is #1.

If all of those steps are in place, you can address where the mold tends to form on your grout for clues. The path of water never lies, because it always flows the way of least resistance. This will help you in diagnosing a problem, because if the water is getting between the tub and the grout or tile, the path of the water will show that to you. To see what I mean, here is a little diagnostic experiment to conduct:

Take a small cup of water and pour it slowly where the mold/mildew tends to grow on your grout. If the water pools up against and sits on the grout line, your issue is likely that water just flows there and you aren’t drying the bathroom well enough. To solve this, you can use a squeegee post shower  or you can use a towel to dry the shower after you finish using it. On the other hand, if you pour your water and it flows into and disappears into a crack or behind the grout line quickly, you may have an issue with leaking into the wall around the tub. You will want to notify your landlord, as the tub should be resealed or moisture intrusion should be investigated further. Time is of the essence, though, so you may just want to spend $10 at Home Depot and seal it yourself in the interim.

When Additional Testing and Inspections Are Worth Considering

If all else fails and the mold/mildew continues to be problematic, (aka doesn’t go away for long and causes symptoms) you may want to conduct some testing and inspections in the bathroom. This would probably seem like overkill for some people, but since you have a CIRS history, I feel that it is warranted.

First, you can get in there like a detective and look around all plumbing for signs of leaks. Touch pipes and the areas around them to feel for moisture or dripping. Walk around carefully on the flooring to see if there are any “soft” spots or lose tiles that could indicate previous or current water damage. Examine the tub/shower and areas inside of it for loose tiles or cracked or missing caulk. These things can indicate water penetration into the wall. Run the sink and flush the toilet and watch the pipes as the water flows through and into them for drips or leaks. Even the smallest drop can be problematic over time. Other leak indicators can be rust and discoloration on pipes or around the walls where the pipes enter. Another thing you can do is to make sure that your toilet doesn’t shift or move with weight on it. This can indicate a leak or can indicate that the seal below it is cracked and needs replacing. If you find any significant issues, you will have to address them or ask your landlord to do so.

After you do that visual inspection, you can do some testing, if you wish.

You can do this by purchasing some inexpensive mold test plates or some “medium” expensive diagnostic plates to take some air samples of the bathroom. If you have really high counts, or the presence of certain molds (this will only be evident in diagnostic testing) that indicate water damage, you will need to call your landlord to discuss having a professional come in for further investigation. In the meantime, since landlords do not always act with urgency, you can employ Band Aid techniques, like fogging with EC3 Mold Solution or burning EC3 Air Purification Candles to get the spore counts down for the time being.

I sincerely hope that all or at least some of that info helps you.

Good luck!


Have you had reoccurring bathroom mold issues? Humidity problems that were not solved with bathroom exhaust fans? Cleaning tips that I didn’t think of? I would love to hear from you. Comment below or email me at catherine@moldfreeliving.com.



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