That pink or salmon-coloured slime in your shower, around your bath drain, or on your shower curtain isn’t actually mould at all — but it can be just as problematic. If you’re scrubbing it away only to find it returns within days, you’re dealing with a persistent organism that thrives in exactly the conditions your bathroom provides. Here’s what pink “mould” really is and how to eliminate it for good.
What Is Pink Mould?
Despite its common name, pink mould is actually a bacterium called Serratia marcescens. This airborne bacterium feeds on fatty substances found in soap scum and shampoo residue. It appears as a slimy pink, orange, or salmon-coloured film, typically in areas that stay consistently damp — shower tiles, bathtub surfaces, grout lines, toilet bowls, and around bathroom fixtures. Unlike true mould, it doesn’t penetrate into surfaces but forms a biofilm on top of them.
For comparison with actual mould species like green mould in your home, true moulds have fuzzy, textured surfaces and penetrate into porous materials, while Serratia forms smooth, slimy films.
Health Concerns
Serratia marcescens is generally not dangerous for healthy individuals. However, it can cause urinary tract infections, wound infections, and respiratory infections in immunocompromised people, the elderly, and hospital patients. If anyone in your household has a weakened immune system, addressing pink bacterial growth promptly is important. The organism can also indicate broader hygiene and moisture issues in your bathroom that could support the growth of more dangerous true mould species.
Why It Keeps Coming Back
Pink bacteria returns persistently because the conditions in a typical bathroom are perfect for it: warmth, moisture, and an endless supply of soap and shampoo residue as a food source. Standard cleaning removes the visible biofilm but doesn’t eliminate the bacteria from the air or from microscopic colonies in grout and caulking. Without changing the underlying conditions, regrowth is virtually guaranteed within days.
If you’re also seeing true mould alongside the pink staining, bathroom mould removal services can address both issues comprehensively.
Effective Removal Methods
To remove pink bacteria effectively:
- Mix a paste of baking soda with dish soap and scrub affected areas with a stiff brush
- Spray with undiluted white vinegar and let sit for 10 minutes
- For stubborn areas, apply a hydrogen peroxide solution (3%) and let sit for 30 minutes
- Rinse thoroughly and dry all surfaces completely
- Replace degraded silicone sealant and grout where bacteria has penetrated
Use our check your mould risk to understand whether your situation warrants professional attention.
Long-Term Prevention
Keeping pink bacteria at bay requires changing your bathroom environment. Run the exhaust fan during and for 30 minutes after every shower. Squeegee walls and glass after each use. Switch to liquid soap (bar soap leaves more residue). Clean bathroom surfaces weekly with a vinegar-based solution. Ensure adequate ventilation — if your exhaust fan is inadequate, upgrading it is one of the most effective investments you can make.
For a comprehensive approach, see our guide on how to mould-proof your bathroom, which covers ventilation, materials, and maintenance strategies that prevent all types of biological growth.
Need Professional Help?
If you’re dealing with mould in your home, don’t wait for it to get worse. Our Hobart-based mould removal specialists are ready to help you reclaim a safe, healthy living environment. Take our free mould risk assessment to understand the severity of your situation, or contact us directly for a no-obligation consultation.