This Overlooked Bathroom Spot Could Be Hiding Mold—Here’s Why It Matters

The idea of mold growing around your home is a disturbing thought. Not only does mold look gross, but having a mold issue in your home can potentially make you sick and cause long-term health problems. That’s why it’s important to identify and tackle any mold growth in your home right away. While you might not like the idea of going around your house searching for mold growth, if you suspect your home has an issue (especially if your space has poor ventilation and high humidity levels), then it’s better to get to the bottom of things as soon as possible. Mold and air quality expert Michael Rubino told us where to look for mold growth in your home—including one spot you’d probably never think to check.

The Unexpected Place to Check for Mold

When you think of checking for mold in your home, the bathroom is probably the first room you’d check. But would you think to look inside the toilet tank? Rubino says you should. Since there’s minimal air exchange between the inside and outside of the toilet tank, meaning there’s less opportunity for mold to find it’s way in, he says mold growth in the tank likely means there’s a bigger issue at hand. “A stray mold spore could find its way in, but if you spot mold growth inside the tank, it’s more likely that high levels of spores are circulating in your home’s air due to an existing mold problem,” he says.

If you do find mold growing inside your toilet tank, it’s a good idea to check other areas around your home and consider calling in a professional to advise you on further steps to take to improve the conditions in your home.

Other Places to Check for Mold in Your Home

If you want to do a thorough inspection of your home for mold growth, there are several places you should look (beyond the toilet tank). Rubino suggests grabbing a flashlight and checking these specific spots:

• Inside the HVAC and in ductwork 
• Refrigerator water spout or drip pan 
• Underneath carpets 
• Insulation in attics and crawlspaces 
• Underneath or behind dishwashers or washing machines 
• Jacuzzi tub jets 
• Inside closets, particularly areas hidden by storage containers and clothing 
• Exhaust fans 
• AC supply or return vents 
• Any places with little to no airflow and an accumulation of dust

However, even if you don’t see anything obvious in these spots, Rubino says that doesn’t necessarily mean your home is in the clear. “Mold can grow in out-of-sight places, such as inside walls, under floors, or behind cabinets—areas that aren’t visible during a surface-level inspection,” he explains. So, if you’re experiencing ongoing symptoms and believe mold is a likely culprit, don’t let an intitial lack of findings keep you from getting a more thorough inspection.

“A good inspector will spend several hours assessing the home, using multiple types of testing to identify where mold is growing, the extent of the contamination, and what you’re being exposed to,” Rubino says. “These results will give you a full picture of the state of your home and help determine the best course of action for remediating it and restoring it to a healthy indoor environment.”

What to Do If You Have a Mold Problem in Your Home

If you’ve discovered a mold issue in your home, there are a few different things to consider. The first is the size of the mold problem. According to the EPA, a rule of thumb to follow is that if the size of the area is 10 square feet or less, you can likely handle the problem yourself, and if it’s any larger, you should call in a professional. However, if you have health concerns or don’t feel comfortable handling the problem yourself, it’s never a bad choice to leave it to the pros.

Another consideration is the material or surface of the item that the mold is growing on, and whether or not it can be cleaned. Absorbent, porous materials, like carpet or even ceiling tiles, may have to be thrown out completely, since the mold can creep deep into the crevices of porous materials, making them difficult to clean thoroughly.

Finally, for any mold cleanup you tackle on your own, make sure to wear personal protective equipment, including goggles, gloves, and a mask, to limit your exposure to airborne mold.