Pink mold in the shower: what it is, is it dangerous, and how to get rid of it

What is the pink stuff in your shower?

Most people call it pink mold. It is usually not mold at all. North Dakota State University Extension and US water utilities such as Gwinnett County explain that the pink or red slimy film in bathrooms is most often a bacterium called Serratia marcescens, which makes a red pigment.

It shows up in the same places again and again:

• the corners of shower trays and tiles, and along grout lines;
• shower curtains and the rims of bath mats;
• around sink plugholes and soap dishes;
• in the toilet bowl at the water line and under the rim;
• pet water bowls, which can collect soap or food residue.

It is different from the black mold that grows into shower silicone, which is a fungus. The difference matters, because the two need slightly different fixes.

If you see both, deal with both. Pink film often sits on top of the same wet corners where black mold grows.

What causes pink slime in the shower?

The bacteria are everywhere. Gwinnett County Water Resources notes they live in dust, soil and water, and travel through the air. They only build up into a visible film where two things meet: water that sits, and something to eat.

• Soap and shampoo residue. NDSU Extension says the bacteria grow on materials containing phosphorus or fatty substances. Soap scum on tiles and shower curtains is exactly that.
• Surfaces that stay wet. Corners of the shower tray, the base of bottles and the folds of a curtain stay damp for hours after a shower.
• Water that sits still. NDSU Extension explains that when water stands, the chlorine in it fades, and the bacteria survive. That is why it often appears in a guest bathroom that is rarely used, or after you come back from a trip.
• Carbon water filters. Both NDSU and Gwinnett County point out that an activated carbon filter removes chlorine from the water, which can make the film more common. If you have fitted a carbon shower filter or a whole-home filter, expect to clean more often.
• New building work. NDSU Extension also notes it sometimes appears during or after construction or remodelling.

In UAE homes, the summer pattern is familiar: a flat is closed up for weeks, water sits in the toilet and shower traps, and the guest bathroom comes back with a pink ring.

Is pink mold in the shower dangerous?

For most healthy people, the pink film is a cleaning problem, not a health emergency. Gwinnett County Water Resources and NDSU Extension both say Serratia marcescens is not known to cause waterborne disease.

It is not completely harmless, though. The same sources note it has caused pneumonia, wound infections and urinary tract infections in hospital settings. A 2023 scientific review in the journal PeerJ describes it as an opportunistic pathogen. It mainly affects people with a weakened immune system or prior antibiotic treatment, and outbreaks are most often reported in neonatal and intensive care units.

So it is sensible to:

• clean it off when you see it, rather than leave it;
• take extra care in a home with a newborn, someone recovering from surgery, or anyone with a weak immune system;
• keep toothbrushes, contact lens cases and anything that touches your eyes or mouth away from the film.

This guide is not medical advice. If you are worried about an infection or have symptoms, talk to a doctor.

How to get rid of pink mold in the shower, step by step

This is the method given by NDSU Extension and Gwinnett County Water Resources, which cites the American Water Works Association.

1. Ventilate. Switch on the extract fan or open the window, and wear rubber gloves.
2. Scrub first. Use a brush and an ordinary household bathroom cleaner to remove the film and the soap scum under it. The scrubbing does most of the work.
3. Disinfect. Apply a chlorine bleach solution or a bleach-based bathroom cleaner, diluted as the label says. Both sources say to leave it on the surface for 10 to 20 minutes.
4. Rinse well with clean water, then dry the area.
5. Go easy on abrasives. Gwinnett County warns that scratched fixtures make it easier for the bacteria to come back. Use a soft brush or non-scratch pad on acrylic trays and chrome.
6. Deal with the curtain. A plastic or fabric shower curtain with pink edges can be washed if the label allows it. A cheap liner that keeps going pink is often easier to replace.

Safety: never mix bleach with ammonia or other cleaning products. The US EPA warns that mixing them can produce toxic fumes. Use one product at a time and rinse between them.

In the toilet

Clean the bowl, then spray bleach into it and under the rim. Gwinnett County also suggests adding a quarter cup of bleach to the toilet tank, leaving it for 15 to 20 minutes and then flushing a few times. Do not leave bleach in the tank for long, because it damages the rubber seals and valves.

In bath toys

Squeeze toys that hold water stay wet inside, which is the kind of damp, soapy place this film likes. Squeeze them out and let them dry after each bath, and replace any that stay pink or black inside.

Does vinegar or hydrogen peroxide kill pink mold?

Online videos often use white vinegar, baking soda or hydrogen peroxide. The water utility and university sources we checked recommend scrubbing followed by chlorine bleach, and we could not find a primary source that tested vinegar or hydrogen peroxide on this bacterium in a home bathroom.

What we can say is this:

• Scrubbing off the film and the soap scum under it is the most important step, whatever you use.
• If you prefer not to use bleach, clean more often and dry surfaces after every shower, so the film never builds up.
• Never use vinegar and bleach together or one straight after the other without rinsing. Follow the US EPA advice not to mix bleach with other cleaners.

How to stop pink mold coming back

Gwinnett County says that once it is established, the bacterium usually cannot be removed for good, only kept under control. The aim is to take away the water and the food.

• Dry the shower after use. A quick squeegee or towel over the tray, corners and glass removes the standing water. NDSU Extension recommends wiping down and drying sinks and tubs after use.
• Rinse off soap. Rinse walls and the tray after each shower, and do not let bottles sit in puddles. A wire caddy lets them drain.
• Run the extract fan. The US EPA advises running the bathroom fan or opening a window when you shower. Leave the fan on for a while afterwards. Our guide on bathroom extract fans shows simple checks.
• Keep humidity in check. The US EPA advises keeping indoor humidity below 60%, ideally 30 to 50%. A cheap hygrometer tells you whether your bathroom dries out between showers.
• Flush the guest bathroom. Water that sits loses its chlorine. Run the shower and flush the toilet in rarely used bathrooms every few days, and again when you get back from a trip.
• Clean on a schedule. A weekly scrub with a bathroom cleaner stops the film before it becomes visible.

A dehumidifier is not the first fix for pink film, because the problem is wet surfaces right after a shower. It can help in the bedroom next to a windowless en-suite with a weak fan, where steam keeps the whole area damp. Electrical appliances do not belong inside a wet shower room. Our shower mold guide explains when a dehumidifier helps in a bathroom.

When it is more than pink film

Pink film on tiles is a surface problem. These signs point to a moisture problem that cleaning alone will not fix:

• black or green spots on the ceiling, or paint that is bubbling or peeling;
• a musty smell that stays after cleaning;
• mold on the walls of the bedroom next to the bathroom;
• a bathroom that still has fogged mirrors and wet walls an hour after a shower.

Start with our guide to mold on walls in UAE homes to find the source. If the extract fan seems weak or the bathroom never dries, HawaQ offers a ventilation and filtration assessment. If mold keeps returning in several rooms, professional mould testing can show where it is coming from.

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