In many St. Louis homes, one of the first signs of iron in tap water is not a stain in the sink but a crust inside the shower head. The spray holes narrow, the flow turns uneven, and the surface looks orange, brown, or rust-tinted. That buildup can come from iron, from mineral scale, or from a mix of both, and the cleaning approach you choose depends on which one you have. This guide explains how to tell them apart and what to do next.
What iron buildup looks like
Iron oxidizes when it meets air and settles as a reddish-brown or orange deposit. It tends to smear when you wipe it and can feel gritty or flaky. It collects where water sits or slows down, such as on the face of the head, around the rubber nozzles, and in the swivel joint.
Hard-water scale looks different. It is usually white or chalky and forms a crust that resembles dried soap on glass. Scale is made mostly of calcium and magnesium minerals. A head with both problems often shows a white crust with an orange tint underneath.
Simple checks you can do this week
- Unscrew the head and look at the inlet screen and the swivel joint. Orange sediment that rinses off under running water points toward iron or other sediment.
- Soak the head in plain white vinegar until the outside feels loose. White scale usually softens and dissolves. Orange staining often lightens only partly and may stay behind in the holes.
- Compare hot and cold. If the buildup is heavier on the hot side only, check the water heater as well, since heat speeds up both iron oxidation and scale formation.
- Fill a clear glass from a cold tap and watch it for a while. Water that looks clear at first and turns orange as it sits suggests dissolved iron rather than solid particles.
Cleaning without damaging the head
- Use a soft brush on the spray face. Avoid wire brushes, picks, or metal tools that can scratch the finish.
- Go easy with strong acids on plated or decorative finishes. Test any cleaner on a hidden spot first and follow the product label.
- Rinse the head well before reinstalling it so no cleaner residue reaches the water you use for bathing.
- Replace the head if the finish is pitted, cracked, or flaking, since worn surfaces hold deposits more easily.
Why the buildup may come back
If the orange crust returns soon after cleaning, the water is still carrying iron or minerals into the head. Cleaning treats the symptom, while the source is the water itself. Watch the rest of the house too. Stains on sinks, tubs, laundry, or fixtures can show the same pattern and help you see how far the problem reaches.
Getting the water tested
A home test kit can give you a rough sense of iron, but a certified laboratory test gives a clearer answer. Ask the lab to report iron and manganese together, since manganese often appears alongside iron and can leave similar dark or orange marks. Your water provider publishes an annual quality report for the public supply, but that report does not cover your private plumbing, an older building's pipes, or a private well. If your home has a well or older plumbing, a direct test of the water at your tap matters more.
Keep your test results, a photo of the shower head, and notes on when you see the buildup. Those three things make it much easier for a licensed plumber or water specialist to read the pattern without guessing, and they give you a clear starting point for deciding what to do next.