Pink Slime in the Shower: What It Is and Why
Raleigh Water Pros • September 26, 2026 • 9 min read
It shows up as a pink or orange-pink ring at the waterline of the toilet, a slimy film along the shower grout, a rosy edge around the drain. You scrub it off and a week later it is back. Naturally, the first thought is that something is wrong with the water.
Pink slime in the shower is almost never a water supply problem. It is usually a common bacterium that lives on soap film and damp surfaces, and it is a cleaning question far more often than a filtration one. That is true on Raleigh Water in Garner, on Cary’s system in Morrisville, and on Holly Springs town water alike.
This guide covers what the pink film is, where it comes from, whether it is dangerous, how to clean it so it stays gone longer, and the one situation where water treatment actually makes it more common. We sell water treatment, and on this topic the right answer is mostly a bottle of bleach.
What is the pink slime in my shower?
The pink slime in most showers, toilets and sink drains is a film of Serratia marcescens, a bacterium that makes its own red-pink pigment. It is often called pink mold, but it is not a mold.
Gwinnett County’s water department describes it as “a red or pink pigmented bacteria known as Serratia marcescens,” found in soil, dust, surface waters and feces. It multiplies “in any moist location where phosphorous containing materials or fatty substances accumulate.” In a bathroom, that means soap and shampoo residue on grout, shower curtains and drains, and residue in toilet bowls. The same organism shows up in pet water bowls for the same reason.
NDSU Extension’s water quality associate put the pattern plainly: it tends to appear “more commonly when you have your windows open during the summer months,” and in rooms that sit unused, such as a guest bathroom. Both details point to the same thing. It arrives from the environment and grows where water stands and residue builds up.
| Colour | What it usually is | Is it a water question? |
|---|---|---|
| Pink or orange-pink film on surfaces | Serratia marcescens bacteria on soap residue | Rarely; it is a cleaning question |
| Orange or red-brown slime in a well home’s toilet tank | Iron bacteria | Yes, on a private well |
| Black specks or black slime | Manganese, or biofilm in a fixture | Sometimes; test to tell them apart |
Orange slime on a well is covered in our iron bacteria guide, and black slime in our manganese guide. Pink completes the set.
Is it coming from my water?
Usually not. The bacterium comes from the air and surroundings and grows on surfaces where the disinfectant in tap water has had time to disappear. NDSU Extension explains that the bacteria survive in places such as toilets “because the water sits for a period of time, with the chlorine dissipating as it stands.”
Every city system in the Triangle carries a disinfectant residual through the pipes to your tap. Raleigh Water uses chloramine for most of the year and switches to free chlorine for about five weeks in late winter, which our Raleigh chlorine switch guide explains. The Town of Cary’s 2025 water report, which covers Morrisville, shows a chloramine running annual average of 2.96 ppm. Holly Springs’ 2025 report shows a chloramine running annual average of 2.16 ppm. That residual is doing its job in the pipes. Pink film grows after the water has left them: in the damp grout, the soap-coated drain, the toilet bowl that sits for days.
Coloured water coming out of the tap itself is a different problem. On city water, call your utility. On a private well, a laboratory reading is the next step, which our water testing and analysis page explains.
Is pink slime in the shower dangerous?
For most healthy households it is a nuisance to clean, not a health emergency, but it is a real bacterium and deserves real cleaning. Gwinnett County states that Serratia is “not known to cause any waterborne diseases,” while noting it has caused urinary tract infections, wound infections and pneumonia in a small share of patients in hospital settings.
The CDC lists Serratia marcescens among the “opportunistic pathogens of premise plumbing frequently encountered during water-related outbreaks in healthcare facilities.” Opportunistic is the key word: these organisms mainly cause illness in people whose defences are already weakened. If anyone in your home is immunocompromised, recovering from surgery or using medical equipment that touches tap water, ask their doctor how careful to be. This page does not diagnose anything, and neither should a water treatment salesperson.
Pro tip: If the pink ring shows up first in the guest bathroom, that is the tell. Water standing unused loses its disinfectant, which is why flushing a rarely used toilet and running its shower for a minute once a week cuts down on the film noticeably between cleanings.
Unsure whether what you are seeing is pink film, iron or manganese? Request a free consultation and we will look at the water first, then tell you honestly whether it needs treatment at all.
How do you get rid of pink slime for good?
Scrub the residue off first, then disinfect with a chlorine bleach solution, then keep surfaces dry. Both Gwinnett County and NDSU Extension give the same routine.
- Scrub. Clean the affected surface with a household cleanser to remove the soap film the bacteria feed on. Disinfecting over residue does little.
- Disinfect. Apply “a strong chlorine bleach solution” and leave it for 10 to 20 minutes, then rinse thoroughly. Follow the label, ventilate the room, and never mix bleach with other cleaners.
- Treat the toilet. Add a quarter cup of bleach to the tank and the bowl, wait 15 to 20 minutes, then flush. Do not leave bleach standing in the tank; Gwinnett warns that prolonged exposure damages the rubber valves.
- Keep it dry. NDSU’s prevention advice: “Wipe down and dry all sinks and bathtubs after using them, and use a cleaning solution that contains bleach.”
Shower curtains, bath toys, drain stoppers and shower head nozzles collect the same film, so include them. Expect it to come back eventually, because the bacteria keep arriving from the surroundings. It is a routine, not a one-off.
Why can a whole house carbon filter make pink slime worse?
A whole house carbon filter removes the chlorine or chloramine residual from all the water in the house, so the water in your shower and toilet has no disinfectant left to slow the bacteria down. This is the part water treatment companies tend to skip.
NDSU Extension notes that activated carbon filters remove chlorine, “potentially supporting bacterial growth.” Gwinnett County says the same: the bacteria thrive when chlorine is removed by activated carbon, and home filtration that removes chlorine has been associated with more Serratia. That applies to catalytic carbon on chloramine as much as standard carbon on chlorine. It is not a defect; it is what the filter is for.
What that means in practice:
- If you have whole house carbon and see more pink film, it is probably the trade-off, not a failed filter. Clean more often, and ventilate the bathroom.
- If your only complaint is drinking water taste, a point-of-use filter at the kitchen sink handles taste while leaving the disinfectant in the shower and toilet water. Our carbon filtration page explains both approaches.
- If you want whole house water filtration for chlorine smell in the shower, that is a reasonable choice, and a slightly stricter cleaning routine comes with it. We would rather you hear that before you buy than after.
No filter removes pink slime from a shower. Anyone offering one as the fix for this problem is selling the wrong thing.
Frequently Asked Questions
What causes pink slime in the shower?
A bacterium called Serratia marcescens that feeds on soap and shampoo residue in damp places. It arrives from the environment, not usually from the water supply, and it grows fastest where water stands and the disinfectant has faded.
Is pink slime in the shower dangerous?
For most healthy people it is a cleaning nuisance. Gwinnett County says it is not known to cause waterborne disease, though it has caused infections in hospital settings. If someone in the home has a weakened immune system, ask their doctor how careful to be.
Is pink slime a sign my water is contaminated?
Usually not. Triangle utilities, including Cary’s system serving Morrisville and the Holly Springs town supply, carry a disinfectant residual to the tap. The film grows afterwards, on surfaces where water sits. Coloured water from the tap itself is a different question for your utility.
Why does pink slime keep coming back?
Because the bacteria are all around and keep landing on damp, soapy surfaces. Scrubbing the residue before disinfecting, drying surfaces after use, and running rarely used fixtures weekly all stretch the time between cleanings.
Will a water filter get rid of pink slime?
No. A whole house carbon filter can make it more common because it removes the disinfectant, a point NDSU Extension and Gwinnett County both make. Our whole house filtration cost guide covers what those systems are actually for.
Is pink slime the same as the orange slime in a well toilet tank?
No. Orange or red-brown slime in a home on a private well outside Garner or elsewhere is usually iron bacteria, which is a water treatment question. Pink film on grout and drains is a cleaning question.
Sources
Read or checked 26 September 2026.
- Gwinnett County Department of Water Resources, Water Quality Facts About Serratia marcescens: what it is, where it grows, carbon filters and chlorine, health in hospital settings, cleaning and prevention.
- NDSU Extension, Red Substance in Tub, Toilet is Bacteria, Roxanne Johnson, 9 August 2010: seasonal and unused-bathroom patterns, chlorine dissipating in standing water, carbon filters, cleaning steps.
- CDC, Outbreaks of Infections Caused by Water-Related Organisms in Acute Care Hospitals: Serratia marcescens listed among opportunistic pathogens of premise plumbing in healthcare outbreaks.
- Town of Cary water report and Town of Holly Springs drinking water, 2025 reports: chloramine running annual averages. Raleigh Water’s annual reports for its disinfectant.
Pink Slime in the Shower: When to Call Us, and When Not To
Pink slime in the shower is a cleaning job in almost every home in Raleigh, Cary, Morrisville and Holly Springs. Scrub, disinfect with bleach, keep things dry, and do not let anyone sell you a filter to fix it.
If you are weighing whole house carbon, or you are seeing orange or black slime on a well, that is a water question and we are glad to help. Book a free consultation and get an up-front written price only for what your water actually needs.
Call (984) 384-6991 or book your free consultation.
