What hard water does to your home and how to deal with it

Cloudy shower doors, persistent toilet bowl stains and white buildup around kitchen faucets can remain even after regular cleaning. Though these marks are often blamed on soap residue or normal wear and tear, they are usually caused by the water itself. CLR Brands looks at why hard water forms and what homeowners can do about it.

Hard water is loaded with dissolved minerals, especially calcium and magnesium, which can leave deposits on fixtures and inside appliances that use water. The amount of buildup and how fast it appears depends partly on where you live and where your water comes from.

The path hard water takes

Hard water begins with rainfall. As rain moves through the atmosphere, it picks up carbon dioxide and becomes a weak carbonic acid. When that slightly acidic water passes through soil and rock such as limestone and chalk, it dissolves calcium and magnesium ions.

Municipal treatment makes water safe to drink, but it does not always remove those dissolved minerals. Unless the water is softened, calcium and magnesium can still travel through household plumbing.

Which parts of the U.S. have hard water?

According to data from the U.S. Geological Survey, more than 85% of American homes have some degree of hard water, although the severity varies with local geology.

The most mineral-heavy water in the country is found in the Southwest and Mountain West. States such as Arizona, Nevada, New Mexico and Utah have groundwater rich in calcium and magnesium, and the dry climate can further concentrate those minerals in water sources.

Texas and the South-Central region are also major hard-water areas, where limestone and dolomite bedrock release large amounts of minerals into local supplies as the rock dissolves. In the Midwest and Great Plains, states including Indiana, Kansas and Nebraska sit on ancient sedimentary seabeds and limestone formations that leach heavy minerals into water sources.

Some major cities known for very hard water include Indianapolis, Las Vegas, Minneapolis, Phoenix and San Antonio.

By contrast, parts of the Pacific Northwest, including Washington and Oregon, often have naturally softer water because of granite-based aquifers and snowmelt. Parts of New England, including Maine, New Hampshire and Vermont, along with some areas in the Southeast, also tend to have softer water sourced from surface water and rainfall. To understand what is coming from your tap, contact your local water utility for the hardness level.

How it shows up around the house

The harder the water, the faster mineral deposits build up on household surfaces. When mineral-rich water evaporates on faucets, showerheads, tile or glass, it leaves behind a crusty off-white residue known as calcium scale or limescale.

Over time, these deposits can cause more than just visible staining:

• Restricted water flow: As scale builds up inside showerheads and aerators, it reduces water pressure and creates uneven spray patterns.
• Surface etching: If hard-water spots on glass shower doors and porcelain fixtures are left untreated, they can etch the material, leaving permanent hazing or scratches that cannot be buffed away.
• Soap scum formation: When hard-water minerals react with fatty acids in soap, they create an insoluble soap scum. This cloudy film sticks to bathtub walls and shower curtains and can encourage mildew growth.

Rust and chemical reactions

Not all mineral stains are white or gray. Reddish-brown streaks and rings in toilets, sinks and bathtubs can come from high levels of dissolved iron in the water supply. When iron is exposed to oxygen and moisture, it oxidizes into iron oxide, or rust, which bonds tightly to porcelain and ceramic.

One common homeowner mistake is trying to remove rust stains with chlorine bleach. Bleach does not dissolve iron oxide. In fact, its oxidizing action can push the chemical reaction further, setting the rust stain deeper into the surface and making it much harder to remove.

The hidden cost to major appliances

Although hard-water spots on shower doors are easy to see, the most expensive damage often happens inside appliances that depend on water, including dishwashers, washing machines and water heaters.

Heating hard water can cause mineral scale to form on heating elements, internal parts and spray arms. Over time, that buildup can lead to:

• Energy inefficiency: Scale acts as insulation. According to the National Board of Boiler and Pressure Vessel Inspectors, just one-eighth of an inch of scale on a water heater coil can raise energy use by up to 20%, because the unit has to work harder to heat water through the mineral barrier.
• Appliance failure: Internal buildup can reduce water flow, clog valves and cause pumps to overheat, sharply shortening the life of major household appliances.

How to reduce buildup

Controlling mineral buildup starts with using the right cleaner for both the deposit and the surface. Standard all-purpose sprays usually are not strong enough to remove mineral scale. Getting rid of mineral deposits typically requires specialized acid-based formulas that break the bond between the minerals and the surface without harming the finish underneath. Some products are made specifically for this job, and some work better than others. Look for effective options that are safer for people, pets and the environment, such as EPA Safer Choice-certified products, which can dissolve heavy calcium and lime without harsh toxins.

Routine cleaning with products made to remove calcium, lime and rust can help keep water flowing properly, prevent permanent etching on glass and tile, and protect plumbing and appliances from early failure.