Why you have pink stains in your toilet and shower, and how to get rid of them
The pink film is a bacteria called Serratia marcescens. It comes from the air and grows on surfaces that stay damp. Penn State Extension says it's not a water quality problem, so filters and well treatment won't stop it. Clean with a chlorine-based cleaner and keep surfaces dry.
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Step 1: Check where the pink shows up
Penn State Extension describes it as pink slime on fixtures, at the toilet waterline, and on sink and shower surfaces. It grows where surfaces stay wet between uses.
If the pink film is on surfaces that get wet and stay wet, and the water itself looks clear, it's very likely Serratia marcescens.
The bacteria come from the air
Penn State says the pink slime is airborne bacteria growing on surfaces that are regularly moistened, and it calls this "not a water problem." That means a filter, softener, or shock chlorination won't fix it.
Step 2: Make sure it isn't something else
A few things can look pinkish or reddish. These do point to the water:
| What you see | What it may be |
|---|---|
| Orange, red, or brown slime inside the toilet tank, with a swampy smell | Iron bacteria in the well. See slimy residue. |
| Red-brown or orange stains that build up, not slimy | Iron. See orange or brown stains. |
| Blue-green stains | Copper from corrosive water. See blue-green stains. |
Iron bacteria grow inside the toilet tank, where the water sits. Penn State calls the back of the tank an ideal place for them. Pink film shows up on surfaces that stay damp.
Step 3: Clean it and keep surfaces dry
Penn State's fix is to clean and dry surfaces often and use a chlorinated cleaner. The film comes back on surfaces that stay damp, so wiping them dry after use helps.
Never mix chlorine bleach with acid cleaners. The Minnesota Department of Health gives this warning about well treatment chemicals.
Test your water if anything else has changed
Pink film on its own doesn't call for a special test. Minnesota recommends a coliform bacteria test every year anyway, and any time your water changes in taste, smell, or look. The EPA notes your local health department may test for free.
Once results come back, our free explainer walks through each number.
If you see orange or brown slime inside the toilet tank as well, the slimy residue page covers iron bacteria, which do live in the well.
Questions people ask
Is pink mold in the shower from my well water?
No. Penn State says pink slime comes from airborne bacteria (Serratia marcescens) growing on damp surfaces, and calls it "not a water problem."
Will shocking my well get rid of pink stains?
No. Shocking treats bacteria in the well. The pink film grows on wet surfaces in the bathroom, so cleaning with a chlorine cleaner and drying surfaces is what Penn State recommends.
Why does the pink ring keep coming back in my toilet?
The waterline in the bowl stays wet all the time, which is where the bacteria grow. Penn State recommends cleaning often with a chlorinated cleaner.
Where this comes from
- Penn State Extension, Common Drinking Water Problems and Solutions
- Penn State Extension, Iron and Sulfur Bacteria, a Slimy Problem
- Minnesota Department of Health, Iron Bacteria in Well Water
- Minnesota Department of Health, Bacterial Safety of Well Water
- Minnesota Department of Health, Copper in Drinking Water
- EPA, Protect Your Home's Water