Hard water in Cottonwood, AZ
Reported by Cottonwood Municipal Water CW1 · July 2025
- AZ typical
- 180 mg/L
- EPA health violations since 2016
- 4
- Softener for 3 people
- 24k grain
- Data
- Utility report
The water in Cottonwood carries roughly 179 mg/L of dissolved calcium and magnesium, or 10.5 grains per gallon. That is hard water. The number comes from Cottonwood Municipal Water CW1, dated July 2025.
At 179 mg/L, Cottonwood is close to the typical Arizona figure of 180 mg/L. Of the 10 nearest cities we track, 8 have softer water and 2 have harder. The range nearby runs from 75 mg/L in Sun City to 237 in Phoenix.
What 179 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 179 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.
3 people × 75 gallons a day × 10.5 gpg = 2,356 grains a day. A 24,000-grain unit regenerates about every 10 days.
EPA record for Cottonwood's water system
4 health-based violations since 2016
Serves about 11,288 people from groundwater.
- Health-based
- 4
- Monitoring or reporting
- 6
- Open now
- 0
| Contaminant or rule | Violations | Period | Status |
|---|---|---|---|
| Arsenicnaturally occurring metal | 4 | 2020–2021 | Resolved |
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 Cottonwood water hard?
Yes. It measures about 179 mg/L (10.5 grains per gallon), which the USGS classes as hard.
What is the water hardness in Cottonwood in grains per gallon?
About 10.5 gpg. One grain per gallon equals 17.1 mg/L, so 179 mg/L divided by 17.1 gives 10.5.
What size water softener do I need in Cottonwood?
For 3 people using 75 gallons each per day, 10.5 gpg works out to about 2,356 grains a day. A 24,000-grain softener covers that with a regeneration about every 10 days.
Has the Cottonwood water system had EPA violations?
EPA records show 4 health-based violations for Cottonwood Municipal Water CW1 since 2016, involving Arsenic. There were also 6 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Prescott Valley109 mg/LModerately hard
- Prescott104 mg/LModerately hard
- Flagstaff161 mg/LHard
- Scottsdale172 mg/LHard
- Sun City75 mg/LModerately hard
- Phoenix237 mg/LVery hard
- El Mirage208 mg/LVery hard
- Youngtown75 mg/LModerately hard
- Paradise Valley171 mg/LHard
- Glendale168 mg/LHard
Hardness data: TapWaterData US Water Hardness (utility report, July 21, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.