Slime and staining

Bacteria and fungi present naturally in air and water can attach to damp surfaces and multiply to form a visible black slime or stain in various colours (black, red, pink). These growths are known as biofilms or ‘microbial slime’ and are most commonly seen in bathrooms and kitchens. Some biofilms can grow into certain materials and become a permanent feature. Although these biofilms can appear very unpleasant they are generally harmless and do not pose a risk to health.

For more information, including details of how to prevent biofilm growth and how to remove them, please see the factsheet on slime and staining.

We also have an easy-to-read guide which explains how you can keep your tap water in tip-top condition.

If you are concerned about the quality of your water please call us on 0345 6723 723. Dial 18001 first if you have hearing or speech difficulties.

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