Clean walk-in shower in polished white subway tile with frameless glass and brass fixtures, built by Nomi

Black mold in the shower: how to clean it, and how to stop it

Guide · Updated

You can clean mold off a shower. You cannot keep it away unless you stop the water that feeds it. Here is how to do both.

01

Why mold loves a shower

Mold needs three things: water, warmth and something to hold onto. A shower has all three.

The black spots usually start in grout lines and caulk, where water sits the longest. Cleaning removes what you can see. If water is also getting behind the tile, the mold keeps growing where you cannot reach it, and it comes back.

02

How to clean it safely

For mold on the surface, any of these work. Wear gloves, open a window or run the fan, and scrub with a stiff brush.

CleanerHow to use it
BleachMix 1 part bleach with 10 parts water. Scrub the spots, then rinse.
White vinegarSpray it undiluted. Let it sit for an hour, then scrub and rinse.
Mold cleanerFollow the label on a store-bought cleaner made for mold.

Never mix bleach with vinegar or with ammonia. The fumes are toxic. Use one cleaner, rinse well, then use the next another day.

The EPA says a homeowner can usually clean an area under about 10 square feet. Larger than that, or if anyone in the home has asthma or allergies, call a professional. The EPA guide to mold

Black mold in the caulk and grout at the base of a tiled shower, next to the shower door track
Groutless Dekton shower wall with a long recessed niche trimmed in brass
03

Keep it from growing back

  • Run the exhaust fan during your shower and for 20 to 30 minutes after
  • Squeegee the walls and glass after each shower
  • Leave the door or curtain open so the shower dries
  • Wash or replace a fabric shower curtain and liner often
  • Replace caulk that has turned black, peeled or cracked

These keep surface mold down. They cannot help if the water is already behind the wall.

04

When it is behind the wall

If mold comes back days after you clean it, the problem is usually not the surface.

Other signs: tile that is loose or sounds hollow, grout that keeps cracking, soft spots in the wall, and a musty smell that will not go away. Each one points to water getting behind the shower.

How the shower was built decides most of this. A shower built on moisture-resistant green board lets water reach the wall over time. One built with a waterproof sheet system behind the tile does not. How showers are waterproofed

05

How we stop it for good

We take the shower down to the studs, so any wet or moldy material comes out. Then we waterproof the floor and walls with an advanced waterproofing system, and finish in tile or in groutless Dekton slab, so there is far less grout for mold to hold onto. About groutless showers

A shower remodel runs $15,000 to $25,000, and most take 1 to 2 weeks. Design, labor and materials are all included.

“What’s more, NOMI used Dekton slabs on the walls and floors, and let me tell you, it’s a breeze to clean, and it looks incredibly luxurious.”

Moe & Michael

Questions

How do I get rid of black mold in my shower?

Scrub it with 1 part bleach to 10 parts water, or with undiluted white vinegar left on for an hour. Never mix the two. If it comes back within days, water is likely getting behind the wall.

Why does mold keep coming back in my shower?

Cleaning removes surface mold. If water gets into the grout, the caulk or behind the tile, mold keeps growing where you cannot reach it.

Can I clean shower mold with vinegar?

Yes. Spray undiluted white vinegar, let it sit for an hour, then scrub and rinse. Do not use it together with bleach.

When should I call a professional?

The EPA suggests calling one when mold covers more than about 10 square feet, when it is inside the walls, or when someone in the home has asthma or allergies.

Does a groutless shower stop mold?

It removes most of the grout where mold starts, and Dekton is non-porous. Good waterproofing behind the walls and a bathroom fan do the rest. About groutless showers

How much does a shower remodel cost?

A shower remodel runs $15,000 to $25,000, in tile or in groutless Dekton slab. Design, labor and materials are all included. Most take 1 to 2 weeks in your home. About shower remodels

Where do you work?

Dallas-Fort Worth and the surrounding area, including Dallas, Fort Worth, Plano, Frisco, Southlake, Westlake, Highland Park, Prosper, and Addison.

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