Hard water in Westminster, CO: what it does to your plumbing

November 5, 2026 · 5 min read · By Westminster Plumbing Experts

What the city's water report says

Westminster publishes an annual water quality report. The 2024 report lists the city's water hardness at about 112 to 149 milligrams per liter, which works out to roughly 7 to 9 grains per gallon. In plain terms, that is water with a fair amount of dissolved calcium and magnesium, the minerals that make water "hard."

The city draws its raw water from Standley Lake and treats it at its Semper and Northwest water treatment facilities. Treatment makes the water safe to drink, but it does not remove the minerals that cause hardness. Hardness is mainly a nuisance for pipes and appliances, not a safety issue. For the full list of results, read the city's report itself.

How scale forms and where you notice it

Scale forms when hard water is heated or when it evaporates. The minerals come out of the water and stay behind as a hard, chalky layer. The hotter the water, the faster it happens, which is why water heaters feel the effect first.

• Storage water heaters. Minerals settle as sediment on the bottom of the tank and coat the heating elements. Typical signs are popping or rumbling noises, hot water that runs out sooner, and slower heating.
• Tankless water heaters. Scale builds up on the heat exchanger and narrows the passages. Units can lose performance or shut down with an error code.
• Faucets and showerheads. White crust around aerators and spray holes reduces flow and spreads the spray unevenly.
• Fixtures and glass. Spots on shower doors, a ring in the toilet bowl and cloudy glassware are the visible signs.
• Dishwashers and washing machines. Scale can build up inside, and hard water makes soap less effective.

Scale, rust or a leak? Telling them apart

Hard water is easy to confuse with other water and plumbing problems, and the difference matters because the fixes are different. Scale is white or grey, chalky and crusty, and it builds slowly. Rust-colored water or brown stains point to corroding pipes or a tank that is rusting, which is a sign of wear rather than hardness. A sulfur or rotten-egg smell in hot water only is often a water heater issue, and a plumber can tell you whether the anode rod is involved.

A leak is different again: it produces moisture. Damp floors, a stain spreading on a ceiling, a hissing sound or a water bill that climbs with no change in your routine are leak signs, not scale signs. If you are unsure which one you have, describe what you see and ask. A short description is usually enough for a plumber to say whether it can wait.

What a plumber can do about it

A plumber cannot remove the minerals from the city's water supply, but there are ways to limit what they do to your equipment. For a storage water heater, a plumber may suggest flushing the tank on a schedule that fits your water, checking the anode rod, and keeping the temperature at a moderate setting. For a tankless unit, the manufacturer's maintenance instructions usually call for periodic descaling, and a plumber can do that work.

Some homeowners consider a whole-house water softener. It is a bigger decision, with trade-offs in cost, maintenance, space and a drain connection, so ask a plumber what it would involve in your home. In Westminster, the Building Division says a permit is required to put in a whole-house water softener, so ask who will pull it. Our guide to choosing a plumber explains what to ask about licenses and permits.

Questions to ask a plumber about hard water

• How much scale is in my water heater, and has it already damaged the tank or the heating elements?
• How often should I flush the tank, given Westminster's water and the age of my unit?
• If I replace my water heater, does the manufacturer's warranty depend on maintenance?
• Would a water softener make a difference in my home, what would it involve, and who pulls the permit?

When scale is a reason to call

Scale is a slow problem, so there is rarely a rush. It becomes a reason to call when the symptoms stack up or when a part fails.

• A water heater that pops, rumbles or bangs, or that takes noticeably longer to heat. See water heater repair.
• A water heater past its mid-teens that is losing capacity. See water heater replacement. The Department of Energy puts the usual life of a storage heater at 10 to 15 years.
• A faucet or showerhead with weak flow that does not recover after cleaning. See plumbing repair.
• Water around the base of a tank. That is a leak, not scale. Treat it as urgent and read emergency plumbing.