How to Recognize Mould in Your Bathroom

By Editorial Team

Updated on September 5, 2024

Mould doesn’t just grow any place, any time. It has conditions! Although moisture is the leading cause, mould finds other ways to build its colony. For the homeowner, this can become a serious problem, as mould isn’t only unappealing, but has serious health implications for yourself as well as your friends and family.

Since the bathroom is a humid room, this is a common place for mould to begin growing and multiplying. If you are concerned that you may have a mould issue, it's important to identify it right away, so you can take the necessary action to get rid of it quickly. Luckily, we’re here to help you recognize the signs that you might have a mould issue in your bathroom.

Do you have mould in your bathroom? This is how to tell!

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There are several factors that contribute to the successful growth of mould. Firstly, it needs a food source. This can be anything from drywall to wood to cotton. Mould looks for dark, humid or warm places, as it cannot grow in ultraviolet light and won't spread as quickly in colder areas of the home.

If your home is in an area where there is a naturally high amount of humidity in the air, then mould growth can be a reoccurring problem. A key factor to mould growth is an excessive amount of water, usually caused by improper drainage or lack of ventilation. Mould grows and forms on damp surfaces within 24 to 48 hours of moisture buildup. Its spores are airborne and can land on organic surfaces close to the original source. It will destroy any surface it settles on, so don't let it hang out too long!  

Where Is Mould Hiding?

You may not always be able to see mould, but you can generally smell it. If your bathroom is smelling overly earthy, stale or, most obviously, mouldy, you are likely experiencing a mould problem. In bathrooms, mould grows on tiles or in surrounding grout. It can be found in both the shower and the bathtub, as grime buildup from body oils and soap scum create a food source for mould to feed on.

Also, excess water build up is a breeding ground for mould, so search places around your tub or shower where water may pool. Also, mould is frequently found in the sink or basin for the same reasons it breeds in tubs and showers.

If you keep many shampoo bottles, bathroom products or soaps alongside the arm of the bath or on shower shelves, this can lead to mould growth. Anything that is frequently getting wet has the potential to aid in the growth of mould. Also, consider any damp cellulose materials, including bath mats, rugs, paper products, wallpaper, and fabrics (towels included!) Make sure bathroom items don't sit in surfaces that are often wet by storing items on higher shelves or surfaces that remain dry.

Make sure to also check for properly draining pipes. Water from leaking pipes, as well as bathroom fixtures such as taps or showers, are a common cause of mould growth. Check undetected or hidden areas, including underneath the sink, around the vanity, across doors to the shower as well as all bath fixtures. Even if your bathroom has a fan, it is important to check around the fan for mould build up. Mould can easily form in one room and spread to another, so think about the rest of your home even if just checking out the bathroom.

Prominent Signs of Water Damage that Lead to Mould

The worst type of mould growth is that which goes undetected, such as colonies behind or inside a wall. Check for any signs of water damage above or around the toilet, bathtub or drains, as well as any noticeable change in the shape of your walls or ceiling. Also look behind wallpaper, behind floor trim and in wall cavities. Ballooning or billowing walls and ceilings could be a potential sign of mould growth, as well as deeper internal problems with your home.

The best way to avoid mould from starting or building up is to have your bathroom properly ventilated and to avoid humidity. If you think your bathroom isn't correctly ventilated, you should check out our tips for proper bathroom ventilation to get rid of that excess water buildup.


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