The measurements, quoted
What the City of Phoenix actually publishes about your water.
Every water treatment company in the Valley will tell you your water is hard. Almost none of them will show you the number, where it comes from, or what it does not mean. The city measures this every year and puts it in a public report. Here it is, quoted, with the link.
Total hardness, 2025
Total Hardness — sample results range 172 – 302 ppm; 10 – 17.6 grains/gallon.
City of Phoenix, 2025 Water Quality Report, “2025 Aesthetic Water Quality Analysis from Distribution System & Secondary Drinking Water Guidelines”“Water hardness indicates the presence of minerals, such as calcium and magnesium, which originate from the soils our source water contacts as it travels to Phoenix’s water treatment plants. These minerals are leached into the water. Hard water can cause some types of scaling in pipes and water heaters, and on plumbing fixtures such as faucets and showerheads.”
City of Phoenix, 2025 Water Quality Report, “Taste, Odor and Hardness”Where that sits on the scale
Hardness is expressed in grains per gallon. Below about 1 grain water is soft; past 10.5 grains it is classed very hard. Phoenix is reported from 10 all the way to 17.6, so the whole city sits at the top of the scale and much of it sits off the end of “hard” entirely.
The part most companies leave out
The same report is explicit that hardness is not a health issue:
“Taste, odor and hardness are not regulated under drinking water health standards. However,
these are harmless, aesthetic aspects that some consumers may notice.”
— City of Phoenix, 2025 Water Quality Report
So the honest case for softening is money and maintenance, not safety: scale on heating elements, shortened appliance life, more soap and detergent, and the film on glass and tile. That is a real case. It does not need to be dressed up as a health scare, and you should be wary of anyone who does.
Two other numbers worth knowing
| Substance | Secondary guideline | Phoenix 2025 range |
|---|---|---|
| Total hardness | None — unregulated | 172–302 ppm / 10–17.6 gpg |
| Total dissolved solids | 500 ppm | 464–716 ppm |
| Sodium | None listed | 91–183 ppm |
Secondary guidelines are non-enforceable recommendations from the EPA, as noted in the report. Figures are the City of Phoenix system; other Valley cities publish their own.
Why those two matter to a quote. A softener does not reduce dissolved solids, so if the water tastes of minerals a softener will not fix it — that is a reverse-osmosis job. And because softening trades hardness for sodium, the 91–183 ppm already present is the baseline you would be adding to. Both facts argue against selling one box as the answer to everything.
The city’s own caution about home treatment systems: “If you choose to install home treatment systems to remove taste and odor or other substances, it is important to note that failure to follow the manufacturer’s instructions concerning operation and maintenance can result in potentially unsafe water.” An unmaintained system is worse than none. That is the argument for servicing what you install, and it is why we quote maintenance alongside equipment rather than after it.
Where your water comes from
Roughly 97 to 99 percent of Phoenix’s water in 2025 came from surface water that mostly started as snowpack: the Salt and Verde rivers via the SRP canal network, and the Colorado River via the Central Arizona Project aqueduct. The remainder came from about twenty city-operated groundwater wells. That blend is why one published number is a range rather than a figure, and why your street can differ from the average.
So what should you do about it?
Measure your own tap first. A city-wide range tells you that you probably have a hardness problem; it does not tell you what size equipment to buy, and buying the wrong size costs money in both directions. Our quote tool sizes from a number and shows the arithmetic; we then confirm it with a test before anything is ordered.
Questions about the numbers
Is hard water dangerous?
No, and the city says so directly: hardness is not regulated under drinking water health standards and is described as an aesthetic characteristic. It is a cost and nuisance problem — scale, soap, appliance life — not a health one. Anyone selling you a softener on fear is misrepresenting their own source.
Why does my neighbour’s reading differ from mine?
Phoenix blends surface water from the Salt, Verde and Colorado rivers with groundwater from about twenty city wells, and the mix that reaches a given street varies. The published figure is a range across the whole system for a reason. Neighbouring cities run their own systems entirely.
What does 17.6 grains actually do?
The city names the effects itself: scaling in pipes and water heaters, and on fixtures like faucets and showerheads. In practice it also means more soap and detergent for the same result, and shorter life from anything that heats water, because scale forms fastest on a hot surface.
Does a softener remove anything besides hardness?
Not meaningfully. It is an ion exchange for calcium and magnesium; it is not a filter and it is not aimed at taste, chlorine or dissolved solids. Phoenix reported total dissolved solids of 464 to 716 ppm against a non-enforceable guideline of 500 — a softener does not change that number. Reverse osmosis is the tool for drinking water.
Should I be worried about the sodium a softener adds?
It is worth knowing rather than worrying. Softening trades hardness minerals for sodium in proportion to the hardness removed, and Phoenix water already carries 91 to 183 ppm of sodium before treatment. For a sodium-restricted household the usual answers are potassium chloride instead of salt, or leaving one kitchen tap unsoftened.