Hard water in Gilbert, AZ

Tap water hardness
168mg/L
9.8gpg
Hard

Reported by Gilbert, Town of · September 2025

AZ typical
180 mg/L
EPA health violations since 2016
3
Softener for 3 people
24k grain
Data
Utility report

Tap water in Gilbert has about 168 mg/L of hardness, which is 9.8 grains per gallon. On the USGS scale that counts as hard. The number comes from Gilbert, Town of, dated September 2025.

Gilbert on the hardness scale, with nearby cities
060120180240300360+AZ typical 180Sun Lakes: 103 mg/LSun Lakes 103San Tan Valley: 109 mg/LSan Tan Valley 109Florence: 109 mg/LFlorence 109Chandler: 139 mg/LChandler 139Paradise Valley: 171 mg/LParadise Valley 171Guadalupe: 172 mg/LGuadalupe 172Scottsdale: 172 mg/LScottsdale 172Queen Creek: 178 mg/LQueen Creek 178Tempe: 180 mg/LTempe 180Maricopa: 220 mg/LMaricopa 220Gilbert 168mg/L as calcium carbonate060120180240300360+AZ 180Sun Lakes: 103 mg/LSun Lakes 103San Tan Valley: 109 mg/LSan Tan Va. 109Chandler: 139 mg/LChandler 139Guadalupe: 172 mg/LGuadalupe 172Queen Creek: 178 mg/LQueen Creek 178Tempe: 180 mg/LTempe 180168 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

At 168 mg/L, Gilbert is 12 mg/L below the typical Arizona figure of 180. Of the 10 nearest cities we track, 4 have softer water and 6 have harder. The range nearby runs from 103 mg/L in Sun Lakes to 220 in Maricopa.

What 168 mg/L means at home

Expect white crust on faucets and showerheads, plus spots on dishes that come out of the dishwasher.

Kettles collect scale quickly. Water heaters build up sediment at the bottom of the tank, which makes them work harder over time.

Soap and detergent need a little more to lather, and soap scum shows up in the tub.

Hardness is not a health problem, and EPA sets no limit for it. It is a matter of scale and soap.

What to do about it

At 168 mg/L most of the trouble is scale, and only a few things deal with it.

Ion-exchange water softener

The standard whole-house fix. It swaps calcium and magnesium for sodium or potassium and needs salt plus a drain. Size it with the calculator below.

Salt-free conditioner

No salt and no drain line. It changes how minerals form scale instead of removing them, so water still tests hard.

Reverse osmosis or carbon filter

Under-sink reverse osmosis removes minerals from drinking water only. Plain carbon filters improve taste but do not soften.

Softener size for Gilbert

3 people × 75 gallons a day × 9.8 gpg = 2,210 grains a day. A 24,000-grain unit regenerates about every 10 days.

Size it for your household

EPA record for Gilbert's water system

Gilbert, Town of · PWSID AZ0407092

3 health-based violations since 2016

Serves about 247,600 people from surface water.

Health-based
3
Monitoring or reporting
222
Open now
1
20162017201820192020202120222023202420252026Surface Water Treatment Rule (LT2)Total trihalomethanes (TTHM)'16'18'20'22'24'26Surface Water Treatment Rule (LT2)Total trihalomethanes (TTHM)
Each dot is one health-based violation, placed at the start of its compliance period.
Contaminant or ruleViolationsPeriodStatus
Surface Water Treatment Rule (LT2)filtration and disinfection12017Resolved
Total trihalomethanes (TTHM)a disinfection byproduct22017Resolved

Health-based means a contaminant above its legal limit or a missed treatment step. Monitoring and reporting violations are late or missing tests and notices. Source: EPA ECHO, 2026Q3 export, violations with periods starting 2016 or later. Full EPA record.

Questions

Is Gilbert water hard?

Yes. It measures about 168 mg/L (9.8 grains per gallon), which the USGS classes as hard.

What is the water hardness in Gilbert in grains per gallon?

About 9.8 gpg. One grain per gallon equals 17.1 mg/L, so 168 mg/L divided by 17.1 gives 9.8.

What size water softener do I need in Gilbert?

For 3 people using 75 gallons each per day, 9.8 gpg works out to about 2,210 grains a day. A 24,000-grain softener covers that with a regeneration about every 10 days.

Has the Gilbert water system had EPA violations?

EPA records show 3 health-based violations for Gilbert, Town of since 2016, involving Surface Water Treatment Rule (LT2), Total trihalomethanes (TTHM). There were also 222 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 42 cities in Arizona

Hardness data: TapWaterData US Water Hardness (utility report, September 15, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.