How to remove black mould from tile grout

Updated July 20, 2017

Many of us have experienced an unwanted house guest -- black mould that makes itself at home in the grout between wall tiles. Though the stubborn moulds like to take up residence in damp places like your bathroom or kitchen, there are ways to remove it from hard to reach places.

Wipe up any water or dampness in the affected area. Inspect the surrounding area for any plumbing leaks, as these are often the source of the mould problem.

Dry the affected area thoroughly with a cloth.

Put on the goggles, and if desired, secure a respirator securely over your nose. Take both of these precautions to protect yourself from airborne moulds and spores while cleaning.

Scrub the affected area with a damp cloth with detergent. Wipe dry and assess your progress. If mould is still visible, try cleaning the area using soap and an old toothbrush, so that you can more closely control the area you are cleaning. Wipe dry.

Mix a small amount of bleach with water in your bucket. Test this mixture on a small portion of tile and grout to make sure it does not discolour the tiles. If it does not cause discolouration, dampen your cloth and scrub again, with either the cloth or toothbrush. Once you have successfully removed the mould, it should not be visible on the tile or the grout, nor should the smell of mould be present.


Allow the bleach solution to soak on the mould-filled area for 10 to 15 minutes before you begin to scrub. This allows the solution to penetrate deep into the grout and kill mould that is further down from the surface.

Using powdered oxygen bleach may be a safer alternative for homes with small children or animals, as it is non-toxic and does not produce harsh fumes. It is also more gentle on the colour of the tile and grout.

To help reduce the chance of developing mould in your home, act quickly to clean up spills and correct leaks in your home; reduce humidity; keep your roof gutters clear; wipe up condensation; and regularly clean tile surfaces with soap and water, and dry completely after washing.


Bleach can produce powerful fumes; it may be helpful to turn on a nearby ventilation fan or open windows while you work on removing the mould with bleach.

Things You'll Need

  • Gloves
  • Goggles
  • Water
  • Soap
  • Towels
  • Small bucket
  • Bleach
  • Old toothbrush
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About the Author

Jamie Christie is a an actor-singer who has performed with nationally known companies in theatre, opera and on the symphonic stage. Ms. Christie earned her B.F.A. in Vocal Performance at Carnegie Mellon Univeristy. In 2005, her views on life at her alma mater were published in Students’ Guide to Colleges (Penguin Books.)