Orange or brown marks on a kitchen or laundry sink can look like iron coming out of the tap, but they often come from something else. In St. Louis homes, the sink itself, the cleaners used on it, and the water running through it can each leave a mark. This guide walks through how to tell them apart before you spend money on a fix.
What the stain usually looks like
Iron staining from water tends to show up as orange, rust-colored, or brownish films that build up around the drain, under the faucet, or in the bottom of the basin. It often wipes off only partly, and it can come back quickly if water keeps running over the same spot. Stainless steel sinks resist rust well, but they are not immune. Tiny particles of ordinary steel, such as from steel wool, a scouring pad, or a dropped tool, can rest on the surface and rust, leaving orange spots that look like they came from the water.
Check the cleaning habits first
Before blaming the water, look at what has touched the sink. Steel wool pads and abrasive scrubbers leave tiny metal fragments. Cleaners that contain bleach or strong chemicals can dull the finish and make small marks easier to see. A quick test is to wipe the stain with a mild, non-abrasive cleaner and a soft cloth. If the stain lifts and the surface looks even, the cause was likely on the surface. If it returns in the same place, keep going.
Look for a pattern in the water
Iron in water usually leaves a consistent pattern. Stains appear in several places across the basin, not just one spot, and they show up mostly where water sits or runs most. Compare the sink with other fixtures in the home. If the bathtub, toilet bowl, and laundry tub also show rust-colored marks, the water is the more likely source. If only the kitchen sink does, the sink, the disposal, or the faucet is the first suspect.
Also pay attention to the water itself. Water that looks clear when drawn but turns orange after sitting in a glass can point to dissolved iron that oxidizes once it is exposed to air. Water that is orange from the start points more toward particles or a plumbing issue.
Simple tests you can do at home
- Draw a clear glass of cold water from the kitchen tap and set it on a counter. Check it again after a while. If it turns orange or cloudy, dissolved iron is a likely cause.
- Run the cold tap for a minute, then check the same glass. Compare it with a sample drawn from a bathroom or outdoor spigot.
- Unscrew the faucet aerator and look for orange flakes or grit. If the aerator is dirty, clean it or replace it.
- Look at the drain strainer and the area under the rim for flakes that come off when rubbed.
Home test kits can give a rough reading, but they are not a substitute for a certified lab analysis when you need a firm answer. A water sample sent to a lab gives a clearer picture, especially if you plan to install any treatment.
What to do next
- Clean the sink with a non-abrasive product and check whether the stain returns.
- Stop using steel wool or metal scrubbers on the sink and switch to a soft pad.
- Check the aerator, strainer, and faucet for flakes.
- Compare with other fixtures in the house to see whether the problem is local or whole-house.
- If the stain keeps returning and other fixtures show the same marks, arrange a water test for iron before choosing any equipment.
St. Louis homes often have older plumbing and mixed materials, so the source of an orange mark is not always obvious. Working through these checks in order will usually narrow the cause before you call anyone. Keep notes about where the stains appear and when they return. That record will help a tester or plumber understand the problem faster.