Mold between bathroom tiles in a shower

Mold in the bathroom

The bathroom has the highest risk of mold formation among all rooms in the house: It can grow on walls, between tiles, on the shower curtain or on the bathroom window.

No wonder; every time we shower or take a bath, the air humidity reaches very high levels. When cooling down, the water in the air condenses, which provides an ideal breeding ground for mold. What to do about it? In the following, we'll explain how to prevent mold in the bathroom or – when it's already there – how to get rid of it while making sure not to endanger your health.

Mold in the bathroom – a common problem

The bathroom by far the most vulnerable room in the house when it comes to mold.

Not only is mold annoying and perceived disgusting, but it's a health hazard as well. Particularly for allergics or people with a weakened immune system. Mold can trigger asthma and many more illnesses.

Unfortunately, mold easily forms in the shower or in the bathroom generally due to the high air humidity and frequent steam occurence. Additionally, the relatively high temperature in bathrooms further promotes mold growth. That makes the bathroom particularly susceptible to mold spores and growth. Whis is why the bathroom requires even more precautions against mildew than other rooms.

A steamped up mirror or window indicates high air humidity. Airing the room thoroughly and regularly after every shower (either by opening the windows or with a ventilator fan) is strongly recommended. Properly heating the room also helps to prevent mold.

Water drops on a shower wall

How to detect mold in the bathroom?

The reason for mold formation is likely water condensing on walls, ceilings or various surfaces. Because mold requires moisture, almost all all wet surfaces are at risk of becoming moldy. If the water cannot properly drain, that also results in increased air humidity because it slowly evaporates.

A strong indicator for mold are black discolored caps between the floor or wall tiles. Mold enters the pores, spreads, and if untreated for long enough, it can even cause the tile gaps to split up. Paint starts crumbling off the wall or ceiling. Heavily infested rooms can start smelling like musty basements.

Mold between bathroom tiles

Mold infested showers

Mold likes to grow in or next to showers because that's where the environment is ideal – warm and humid.

Constantly drawn-together shower curtains or closed shower cubicles increase the risk because it prevents venilation and keeps the humidity high for even longer. After taking a shower, the walls are splashy and warm. Just what mold thrives on.

For this reasons, it's important to consider the following:

  • Wipe down the shower cubicle with a tower after every shower
  • Leave the cubicle door or the shower curtan open for a while after every shower
  • Spread out the shower curtain so it can dry
  • Regularly wipe cubicle walls and tile gaps
  • Install a ventilator fan

Already moldy shower curtains should be disposed of quickly.

Mold next to the shower

Remove mold in the bathroom or shower

Mold remover containing chloride works well when removing mold from tile gaps. Just let it soak for a while, then scrub.

Mold remover containing chloride smell like public indoor pools, just more intensely. Mold remover containing sodium hypochlorite kills off mold quite effectively. After letting it soak in for 15 minutes, the mold is mostly gone and dissolved. Wallpapers and tile gaps can be sprayed on as well (tough wallpapers might get discolored or warped, but mold would do that too anyway). Toroughly air the room while and after applying these chemicals.

Act quickly when confronted with moldy tile gaps

Moldy tile caps should be dealt with imediately, because the soft silicone allows mold to pass through and spread rather quickly. Removing the mold on the surface will not make it go away for long once it got it too deep. The silicone needs to be removed entirely from the tile gaps. Then it can be cleaned with alcohol or chloride, and only then the silicone can be reapplied. That's why you should make sure the mold can't get that deep in the first place.

Clean mold off of bathroom tiles

Protective equipment

All chemical mold removal products should only be handeled while wearing gloves. A breathing mask is recommended because chloride and mold spores can irritate the airways. Chemical mold removers must not come in contact with other cleaning agents as they can chemically react and produce dangerous chloride gas. All rags, brushes etc. that came in contact with mold spores should be disposed of to make sure they don't spread surviving spores elsewhere.

Protective gloves

Prevent mold in the bathroom

Eliminate condensing water

If the air humidity remains high for too long after showering, mold is likely to grow. To prevent mold formation, make sure the walls, windows and surfaces are dry each time after taking a shower or a bath. Wipe off water that condensed to droplets.

Water drops

Air the room thorouthly

Do not stop until windows and mirrors are no more steamed up. Even then, add a few more minutes. It can easily take 5 to 15 minutes until the air humidity returns to acceptable levels.

Do not just tilt the window, but shock-ventilate by fully opening the windows. .

Ideally, you have an automatic air ventilator which disposes of the humid air after taking a shower or a bath.


Do not let towels, rags and clothes dry in the bathroom

Wet towels or washrags evaporate all the water they carry into the air, increasing air humidity. Don't let them dry in the bathroom.


Cleaning the bathroom

The bathroom should be cleaned on a regular basis. Pay extra attention to tile caps, that's where sediments like to accumulate. Small amounts of hair or dust combined with moisture are enough to form an ideal breeding ground for mold.

Wipe off bathroom tiles

Check air humidity with a hygrometer

It's important to regularly check the air humidity in the bathroom. That's what a hygrometer is for. It displays the humidity in percent (some even wirelessly when connected to a station) and it's cheap.

More than 60% humidity means it's too high. Whenever the air humidity exceeds 60%, you should air the room until humidity levels return to normal..


Lower humidity with a dehumidifier

If airing regularly does not suffice, a dehumidifier will do the trick. They extract water from the air and gather it in a tank, decreasing air humidity and thus preventing mold growth.

Don't let the bathroom get too cold

Water in humid air preferrably condensates on cold walls. That's why the temperature in the bathroom should remain constant. Warm air can contain more water. Hence, temperature control is an effective way to avoid mold.

Chalk bricks or loam plaster prevent mold

Chalk plaster is ideal for the bathroom because it can absorb humidity when the room is steamy, and emit humidity when humidity went down again. This promotes a healthy room climate. Also, mold has a hard time growing on chalk because its basic (in chemical terms).


Mold spores can generally occur anywhere in the air. In warm and wet environments like bathrooms, they find perfect living conditions more than in any other room.

High humidity must be vented, or it will necessarily result in a mold problem. Using a hygrometer helps you determin the exact humidity and enables you to respond properly. If other measures do not suffice, a dehumidifier can reliably lower air humidity.

Mold can be removed by spraying it with mold removal agent. But to lastingly get rid of it, the preconditions have to be fixed too.

Once the mold infestation has spread above a certain point, a professional has to come in and renovating the room may be necessary.

Chloride spray