Phoenix Hard Water Guide

Fountain Hills water: what EPCOR's figure means for a softener

Fountain Hills is served by EPCOR Water Arizona's Chaparral City system, a private water company, not a city utility. EPCOR publishes one hardness figure, measured as water leaves its treatment facility.

Fountain Hills water hardness by area

Figures published by EPCOR Water Arizona (Chaparral City water system). The dial setting is the number to enter on your softener.

City or areaHow hardRange (grains per gallon)Softener dial settingSource
Fountain HillsVery hardabout 1616EPCOR Water Arizona (Chaparral City water system), annual water quality report, 2025 (hardness sampled in 2024)

1. Where do you live?

2. How many people live in your home?

the number your kit shows, in grains per gallon
Your water is
Very hardAbout 190 lb of minerals flow into your home each year
Softener size to buy
32,000-grain
the size number on the box
Salt it will use
About 10
40 lb bags a year
Set the hardness dial to
16
recharges about every 8 days

What the dial setting means

Every softener has a control valve on top with a setting for your water's hardness, usually labelled "hardness" or "grains". Enter this number there. It tells the softener how hard your water is, so it knows when it is full.

"Recharging" (some manuals say "regenerating") is the softener cleaning itself: it rinses its resin beads with salty water to flush out the minerals they have caught. With this setting it happens on its own, about every 8 days in your home, usually at night.

Set the number too low and hard water slips through before the next recharge. Set it too high and the softener recharges early, wasting salt and water.

EPCOR gives about 16 grains per gallon for Fountain Hills and says it can change with the seasons. Source: EPCOR Water Arizona (Chaparral City water system), annual water quality report, 2025 (hardness sampled in 2024).

We don't make, sell or install water softeners or filters, and no company pays to be listed or ranked.

How this figure was measured

Who published it

Water authority
EPCOR Water Arizona (Chaparral City water system)
About the authority
The private water company that serves the Town of Fountain Hills and parts of Scottsdale through its Chaparral City water system. A public agency; no company supplied or paid for this figure.
Type of source
Annual water quality report. Every community water system in the U.S. must publish one each year under the federal Safe Drinking Water Act, so it is the utility’s own official record of what is in its water.
Data year
2025 (hardness sampled in 2024)
Last checked
16 October 2026, against the original document

What the figure is

What was measured
Hardness in grains per gallon, measured in the water leaving the treatment facility: about 16 grains per gallon (274 mg/L)
Area covered
The whole Fountain Hills water system
How it was sampled
One figure, measured in the water leaving the treatment facility rather than at the tap.
Where the water comes from
Colorado River water delivered by the Central Arizona Project, plus groundwater pumped from the aquifer below Fountain Hills. EPCOR notes that hardness can change with the seasons because of this mix.

How we use it

Figure we use
Figure as published (about 16 grains per gallon).
Unit conversion
1 grain per gallon = 17.1 milligrams per litre (mg/L), the same as parts per million (ppm)
How we calculate
Daily hardness to remove = people × 75 gallons × grains per gallon. We pick the smallest standard size that lasts about 7 days between recharges, at 3,300 grains removed per pound of salt.
Limits
Hardness varies by street and by season as utilities switch between water sources. A home test result is more exact and overrides this figure.

River water plus local groundwater

The Chaparral City system blends Colorado River water delivered by the Central Arizona Project with groundwater pumped from the aquifer below Fountain Hills. EPCOR notes that because of this mix, hardness and taste can change with the seasons.

One figure, measured at the plant

EPCOR’s figure is measured in the water leaving the treatment facility, not at customers’ taps, and it is a single value rather than a range. Treat 16 as a good starting point and test your own water if scale comes back with your softener set correctly.

Sizing for Fountain Hills homes

At 16 grains per gallon:

  • one or two people: 24,000 grains
  • three people: 32,000 grains, recharging about every 8 days
  • four people: 40,000 grains, about 14 bags of salt a year
  • five people: 48,000 grains; six: 64,000 grains

Parts of Scottsdale too

EPCOR’s Chaparral City system also serves some Scottsdale addresses. If your bill comes from EPCOR rather than Scottsdale Water, use this figure, not Scottsdale’s zone figures.

Common questions

How hard is the water in Fountain Hills?
EPCOR's water quality report for 2025 for the Chaparral City system gives approximately 16 grains per gallon, from a 2024 sample of water leaving the treatment facility.
Who supplies water in Fountain Hills?
EPCOR Water Arizona, through its Chaparral City water system, which also serves parts of Scottsdale.
Does EPCOR soften the water?
No. EPCOR states that it doesn't treat drinking water for hardness.