The pink stuff in your shower is not your water
Updated August 2026
That pink or salmon-colored film in the corner of your shower is a bacterium called Serratia marcescens. It travels through the air, lands on wet surfaces, and feeds on the soap residue sitting there.
Where it comes from and why Louisiana bathrooms grow it
Serratia lives in soil, dust, and air just about everywhere on earth. To build a colony you can see, it needs steady moisture, a surface to cling to, and something to eat. Your bathroom hands it all three. Soap scum, shampoo film, and body oils contain the phosphorus and fatty compounds this bacterium treats as a meal.
Louisiana supplies the moisture. On the Northshore and across the greater New Orleans area, indoor humidity stays high for most of the year, so a shower wall that would dry in an hour out west is still damp when the next person turns the water on.
Here is where it usually turns up first.
- Grout and caulk lines in the shower go pink before anything else does.
- A pink ring forms in the toilet right at the waterline, where the water meets the air.
- Shower curtain folds near the bottom stay wet all day and collect it.
- Pet bowls turn fast, since saliva and kibble crumbs give the colony plenty to eat.
- You will also find it in sink overflow holes and under soap dishes.
How to get rid of it and keep it away
- Scrub the film off with a bathroom cleaner or a diluted bleach solution, roughly a half cup of bleach per gallon of water.
- Give the bleach several minutes on the surface before you rinse, because contact time is what actually kills the colony.
- Wash your shower curtain and liner in the machine on hot.
- Run the vent fan during every shower and leave it on for twenty minutes afterward.
- Squeegee or towel the walls and tub floor when you are done bathing.
The pink will come back. The air keeps delivering fresh bacteria to your bathroom no matter what you clean with, so drying does more for you over a year than any single deep clean. A bathroom that dries out between showers might see the ring once or twice a year. A bathroom with a dead vent fan and a damp floor sees it monthly.
The lookalikes that actually are your water
Some stains people call pink really do trace back to the water. The test is simple. If the color wipes away and returns in the damp corners, it is the bacterium. If it builds up where the water actually runs and scrubbing will not lift it, look at the water.
- Orange or rust-brown streaks under the faucet and along the tub point to iron. Private wells around St. Tammany and Tangipahoa carry it regularly, and the stain sets into porcelain instead of wiping off. Our guide to well water on the Northshore covers what to test for.
- Black specks or gray smudging in the toilet tank and on white laundry usually mean manganese, which tends to travel alongside iron in well water.
- Blue-green stains trailing down from the spout or drain mean acidic water is eating at your copper pipes, and low-pH well water can also put copper into what you are drinking.
- Chalky white crust around the aerator and on the glass door comes from hardness minerals. That one is a system-by-system story around here, since hardness varies a lot from one water system to the next.
What a filter does and does not do here
A whole-home carbon filter will not stop pink slime, and no one should sell you one for that reason.
There is a wrinkle here that runs the other direction, and it is worth knowing before you buy anything. Chlorine in city water keeps Serratia from establishing itself inside the plumbing. A carbon filter takes that chlorine out at the front of the house, so the water reaching your shower has nothing left in it to suppress the bacteria growing on wet surfaces. Homes on whole-house carbon sometimes notice the pink ring showing up a little quicker than it used to. The cleaning routine stays the same either way, and the fix is still the vent fan and a dry surface.
The questions worth asking about filtration are about taste, about staining that traces back to the water itself, and about what your system's published report shows. What we install lays out the equipment and what each piece is actually for.
Questions people ask
Is it dangerous? In a normal household, no. Serratia is not known to cause waterborne illness and does not appear on drinking water contaminant lists. It can cause infections in hospital settings and for people with weakened immune systems, and contact lens wearers should keep their cases clean and dry.
Why does it keep coming back? The bacteria arrive through the air, so cleaning kills what is present without doing anything about what lands tomorrow. How fast your surfaces dry is the only thing that changes the pace.
Why is it worse in my shower than my sinks? A sink drains and dries in a few minutes. A shower holds water in the grout, the caulk, the corners, and the curtain folds for hours, and it gets a fresh layer of soap every single day.
When the stain is a water question
If the ring in your tub is orange rather than pink, or the stain will not scrub out at all, you are looking at a water question. Start with the published testing for the system that serves your address. Find your neighborhood report and see what is actually in the water before you spend a dollar on equipment.