Hard water in Tucson

What the utility reports

Tucson Water's main system is classed "hard to very hard"; its 2024 Annual Water Quality Report puts hardness around 228 mg/L (about 13.3 grains per gallon).

Source: Tucson Water parameter explanation table; Tucson Water 2024 Annual Water Quality Report

How to read the numbers

Tucson Water classifies hardness (mg/L as calcium carbonate) as 0–60 soft, 60–120 moderate, 120–180 hard and 180+ very hard (Tucson Water). To convert mg/L (ppm) to grains per gallon, divide by 17.1 (same source).

Hardness varies by neighborhood and water source, so test your own tap before programming a softener (how to set it).

What hard water does

Phoenix's water report notes that hard water can cause scaling in pipes and water heaters and on fixtures (City of Phoenix). See 7 signs you need a softener, or compare softener vs. RO.