Water Hardness
A measure of dissolved calcium and magnesium in water, expressed in grains per gallon (gpg) or mg/L. Hard water accelerates scale buildup in pipes, water heaters, and fixtures.
Water hardness measures the concentration of dissolved calcium and magnesium ions in your water supply. These minerals dissolve naturally as water moves through limestone and chalk formations. Hard water isn't a health risk — but it causes real plumbing damage over time.
What is the water hardness scale (grains per gallon)?
- 0–1 gpg — Soft (Seattle, Portland, most of New England)
- 1–7 gpg — Moderately hard (Southeast, Pacific Northwest)
- 7–10 gpg — Hard (Midwest, Mid-Atlantic)
- 10–14 gpg — Very hard (Texas, Great Plains, Southwest)
- 14+ gpg — Extremely hard (Phoenix, Las Vegas, West Texas — often 18–25 gpg)
What does hard water do to plumbing?
- Scale buildup in water heaters reduces efficiency by up to 24% (U.S. DOE data) and shortens lifespan from 12 years to 6–8 years in 15+ gpg water
- Calcium deposits clog showerheads, aerators, and ice makers
- Scale narrows copper supply lines over decades — a known problem in Phoenix, Las Vegas, and San Antonio homes built before 1990
- Slab leak risk is elevated in very-hard-water cities — calcium reacts with copper under certain pH conditions, creating pinhole corrosion
How do you test your water hardness?
Municipal utilities publish annual water quality reports (Consumer Confidence Reports) online with hardness data. Inexpensive test kits are available at hardware stores.
What are the solutions for hard water?
Salt-based ion-exchange water softeners remove hardness ions and are the most effective solution above 10 gpg. Salt-free conditioners (template-assisted crystallization) reduce scale without removing minerals — appropriate for 7–12 gpg ranges.
Researching the term is one thing — hiring for it is another. See water softener installation services for scope, timelines, and what drives the price, or call (888) 530-4445 to talk to a local plumber about the job.
For the full picture — materials, process, timelines and what drives the cost — read Water Softener Installation Guide.
What related terms should you know?
What sources back this up?
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