If you have lived in St. Louis for any length of time, you have probably noticed a white crust on a faucet tip or a shower head that sprays unevenly. That crust is mineral scale, and it is one of the most common ways hard water shows up in a home. This guide explains where the scale comes from, which fixtures collect it first, and how to clean and check them without damaging the finish.
Where the scale comes from
Hard water carries dissolved minerals, mostly calcium and magnesium, picked up as water moves through soil and rock before it reaches the local system. Water in the St. Louis area is commonly considered hard, though how hard depends on the source and on your neighborhood. When that water is heated or left to evaporate, the minerals come out of solution and settle as a hard, chalky layer. Scale builds fastest where water is warm and where it dries on a surface, which is why the fixtures in your bathroom and kitchen tend to show it first.
Faucets: aerators and cartridges
Most faucet problems start at the very end of the spout. The aerator is a small screen with tiny openings that mixes air into the flow. Scale collects on the screen and in the openings, and the result is a spray that sputters, splits, or slows down. Behind the handle, many single-lever faucets have a cartridge or valve that can also collect deposits, which can make the handle stiff or cause a drip.
Signs to look for include:
- Uneven or weak spray from the faucet tip
- A handle that feels gritty, stiff, or hard to move
- Water that drips after the faucet is turned off
- White or cloudy specks that collect in the sink basin around the drain
Shower heads and hand sprays
Shower heads are where many St. Louis homeowners first notice a change. Scale plugs the small nozzles, so the water comes out in thin streams or in a lopsided pattern. Hand sprays and the hoses that connect them can build up deposits in the same way, and the flexible parts may become stiff over time. Because a shower head works in a warm, humid space, the buildup can return quickly after cleaning.
Other fixtures that show the buildup
Scale is not limited to faucets and shower heads. Toilet bowls can develop a ring along the waterline, and the inside of a kettle or coffee maker can gather a crust. Dishwashers and washing machines can also collect deposits on heating elements and spray arms over time, which may affect how well they clean and heat water. If you have an older water heater, the heating elements and tank may build up sediment, so it is worth checking the manufacturer's guidance on flushing.
How to clean scale without harming the finish
- Turn off the water supply to the fixture if you plan to remove parts, or close the shutoff valves beneath the sink.
- Unscrew the aerator or shower head and rinse it to remove loose debris.
- Soak the part in a mild acidic solution such as white vinegar for a period of time suited to the amount of buildup, then rinse thoroughly.
- Use a soft brush, such as an old toothbrush, to clear the openings. Avoid sharp tools that can scratch the holes or the surface.
- Wipe the exterior of the fixture with a soft cloth and dry it so the next layer of scale does not form on a wet surface.
- Reinstall the parts, turn the water back on slowly, and check the spray pattern.
Protecting the finish
Many fixture finishes, including polished and coated metals, can dull or stain when exposed to strong cleaners or abrasive pads. Check the care instructions that came with your fixture before using any product, and test a small hidden area first. Avoid mixing cleaners, and never combine acidic and chlorine-based products. Rinse well after any cleaning step.
Checking your own water in St. Louis
Water conditions vary by neighborhood, building, and the age of pipes, so the signs in one St. Louis home may not match the next. A few simple checks can help you understand what you are dealing with:
- Read the annual water quality report that your water provider publishes, which describes the source and general conditions.
- Use a home test kit to get a rough idea of hardness and other common contaminants.
- Send a sample to a certified lab if you want a detailed breakdown of what is in your water.
Any of these steps can help you match a symptom to a likely cause. Keep notes on where and when you see scale, since patterns can point to hot water lines, specific fixtures, or a particular part of the house.
When to ask a professional
If scale keeps returning quickly, if a handle no longer moves, or if you see signs of leaking at a fixture, a licensed plumber can inspect the valves, cartridges, and supply lines. A plumber can also tell you whether the problem is limited to one fixture or spread through the home's water system. This guide is meant to help you understand the problem, not to replace a hands-on inspection.