Your Bathroom’s Hotbed for Mold Is Hiding in Plain Sight

published Mar 14, 2024
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Modern Tiled Bathroom with Shower and Vanity
Credit: Jon Lovette

Although it’s nice to enjoy the aesthetic and psychological effects of a clean home, cleaning isn’t merely about presentation and emotional well-being. Think about the allergy-sufferer who gets better sleep when the bedroom is regularly dusted or the implications of disinfecting high-touch areas when someone in the house has the flu. By removing things from your home that can harm you, cleaning also impacts your physical health. 

This is the case when it comes to dealing with mold. While mold can be a problem anywhere moisture is present, most homes battle mold in the bathroom, which is consistently humid. In particular, as I discovered recently, one of the worst spots for mold and bacteria is the bottom of the shower curtain liner. 

In my home, the shower curtain liner was almost constantly damp, and the results were not pretty: the bottom 8 inches or so became discolored and moldy within months. That strip of grime was the last thing I wanted to shower next to and definitely not something I wanted anywhere near my kids as they were bathing. Although this was a fairly new problem for us, I realize it could be a common scenario for many others. So I reached out to Michael Rubino, a mold and air quality expert and the founder of HomeCleanse, to dig deeper into the topic.

Here’s what he had to say.

Shower curtains are especially susceptible to mold and bacteria growth. 

Mold grows where there’s moisture,” Rubino explains, adding that because shower curtains often get wet, “they’re prime real estate for microbial growth.” Additionally, the makeup of the shower curtain or liner itself, if it’s fabric, along with other factors in the shower, can contribute to the proliferation of mold.

Many types of mold and bacteria thrive in the bathroom — with Aspergillus being the most common species that thrives in humid areas. I spotted pink slimy stuff at the bottom of my shower curtain liner, which as it turns out could be mold or bacteria, too. “Pink mold on a shower curtain could be a species called Aureobasidium pullulans. It could also be a species of bacteria, such as Serratia Marcescens, which is often the most common culprit. These species require lots of moisture to survive, so they pop up in areas with prolonged high humidity and water sources.”

Dealing with mold is critical to your health. 

While it might be interesting to know what kind of mold could be growing in your bathroom, it isn’t necessary. The important thing is that any kind of mold or bacteria in your living space needs to be addressed. “Mold and bacteria colonies release microscopic particles into the air, including fragments, spores, endotoxins, and exotoxins. Some species of mold also release microscopic toxins called mycotoxins when threatened,” says Rubino. 

Mold exposure is nothing to play around with, as it can trigger a multi-systemic immune response, he explains. “Some common symptoms include headaches, coughing, runny nose, watery eyes, rashes, mood swings, digestive issues, brain fog, chronic fatigue, and more.” Even if you don’t think it’s an issue, it can become one or could be affecting others. “Everyone responds differently to mold exposure for a variety of factors. While one person may have no symptoms, another may develop over a dozen. That’s why all microbial growth should be dealt with quickly and correctly,” he says.

It’s also important to deal with mold as soon as you see it. “The longer the growth goes on, the more particles it will release. This lowers the indoor air quality and can cause unwanted exposure as those particles enter the body through inhalation,” says Rubino. 

“Mildew” is no less harmful than mold. 

A “little mildew” is just as much of a concern as any mold problem. “One common misconception is that mildew is not an issue to be concerned about. That is not true,” shares Rubino. Mildew is a specific type of mold that’s light in color — it can be gray, white, or light green — powdery in texture, and grows flat without much height. 

The best way to deal with mold on shower curtains is drastic. 

Rubino’s advice when it comes to dealing with moldy shower curtains might surprise you, as it surprised me: “The best way to deal with mold on a shower curtain is to throw the material away, clean the shower, and replace the curtain with a new one.” 

He explains that mold has root-like structures, called hyphae, that grow on porous materials like shower curtains and can be nearly impossible to remove completely. If left behind, they’ll just grow back, and their particles will embed themselves into the fibers of these materials. “That’s why proper remediation should always include eliminating the colony, root structure, and any particles present.”

Even after you throw a moldy shower curtain away, you need to remove contaminates from the environment. You should clean non-porous surfaces in the shower with a botanical cleaner like Benefect Decon 30 and wipe with a microfiber towel. Semi-porous surfaces like grout can be cleaned with hydrogen peroxide.”

Mold growth prevention is key.

Rubino points out that some species of mold can grow in as little as 24 to 48 hours. “Keeping the shower curtain and bath area dry is key to helping avoid microbial growth,” he emphasizes. He recommends the following to keep mold growth at bay.

  • Choose machine-washable shower curtains.
  • Maintain an indoor humidity of 35 to 50%. You can do so by cracking a door or window and turning on the exhaust fan while showering. This will help remove the humid air from the room and replace it with drier air. If the humidity doesn’t lower to the right level, consider investing in a dehumidifier for the room.
  • Clean the liner, curtain, rod, and rings once a month if applicable.
  • Separate the liner and curtain after showering.
  • Squeegee the shower after use and deep clean the bathroom regularly. Don’t forget to clean the shower head monthly.
  • Check for and resolve structural issues. Things like misaligned tiles and aging grout should be addressed as soon as they’re spotted because they can trap moisture and particles, allowing microbial growth.
  • Wash bath mats, towels, and liners. Use a botanical laundry additive, like Micro Balance EC3 Liquid Laundry Additive.
  • Hang up the shower mat, towels, washcloths, and anything else damp after use.
  • Dust frequently. A layer of grime can contain contaminants like mold spores and bacteria.

After learning what I did from Rubino, I realized I needed to start over with our shower curtain situation. I tossed the old one and bought a no-hook shower curtain, which is both washable and super easy to take down for washing. I can take the whole thing down or unsnap the liner for even more frequent washing, which I plan to do weekly, along with towels and shower mats. 

I feel good knowing that I not only removed a source of potential harm in our home, but also that I’m armed with ways to keep it from being a problem again.