San Diego water hardness calculator
Enter your water hardness in grains per gallon to see where you land on the scale, what it's doing to your home, and what fixes it. Not sure of your number? Most of San Diego County runs 17 to 20+ GPG, so start there.
Find this on a test strip, or convert from your water report: 1 GPG is about 17.1 mg/L (ppm).
What your hardness number means
San Diego's water sits at the top of this scale. At 17 to 20+ grains per gallon, the dissolved calcium and magnesium build scale inside your water heater, behind your showerheads, and through your appliances. It's not a safety problem, it's a wear-and-tear and comfort problem, and it adds up year after year.
The two common fixes are a salt-based water softener, which removes the hardness minerals, and salt-free conditioning, which stops scale from forming without salt, sodium, or brine. Which one fits depends on your water and your home. The honest starting point is knowing your exact hardness, which is what the free in-home water test measures. You can also learn to spot hard water yourself first.
Water hardness questions
How hard is San Diego water?
San Diego County tap water is very hard, commonly 17 to 20 or more grains per gallon. It comes from an imported Colorado River and State Water Project blend, both of which carry a high mineral load. That puts most of the county at the top of the hardness scale.
What is a grain per gallon (GPG)?
A grain per gallon is the standard US measure of water hardness. It counts the dissolved calcium and magnesium in your water. Under 1 GPG is soft, 7 to 10.5 is hard, and anything above 10.5 GPG is very hard. You can find your number on a test strip or convert it from your water utility report (1 GPG is about 17.1 mg/L or ppm).
How do I find my exact water hardness?
Three ways. A hardware-store test strip gives you a rough number in a minute. Your water utility publishes hardness in its annual Consumer Confidence Report, though that is a system average. The most accurate option is our free in-home water test, where a technician measures the water at your tap and shows you the exact reading.
Is hard water dangerous to drink?
No. Calcium and magnesium are not harmful to drink. The problem with hard water is what it does to your home: scale that shortens the life of water heaters and appliances, spotty glassware, and dry skin and hair. Treating it is about protecting your home and comfort, not safety.
Want your exact water hardness?
The free in-home water test measures your hardness, chloramine, and more, right at your tap. No pressure.