Hard Water in Mesa, Scottsdale and San Diego: What the Utilities Report

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Mesa, AZ

The city says hardness ranges from 12 to 22 grains per gallon depending on the water source that serves your area.¹

Scottsdale, AZ

The 2026 Water Quality Report lists approximate hardness of 13–15 gpg south of Indian School Road and 13–17 gpg in the two zones to the north.² The city's drinking water web page shows a higher table (16–25 gpg by zone).³ When sources disagree like this, have your own tap tested before you program a softener.

San Diego, CA

The 2025 annual report shows treatment-plant average hardness of 13.8 to 14.2 gpg.⁴ The city's water quality page describes a typical average of about 16 gpg, varying by area and demand.⁵

Why the numbers move

All three cities blend sources, or serve different neighborhoods from different plants, so hardness depends on where you live. Next: how to set your softener.

Sources

1. City of Mesa: hard water
2. Scottsdale 2026 Water Quality Report
3. Scottsdale Water: drinking water page
4. City of San Diego 2025 Annual Drinking Water Quality Report
5. City of San Diego: water quality

Last reviewed Oct 13, 2026. This is general information, not professional advice. Confirm figures with your utility and installer.