TEST FIRST
What to test your well for before buying treatment
Nobody can tell you what your water needs without a test, and anyone who tries is selling you equipment rather than solving a problem.
- Chino Valley, Williamson and Paulden
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Call (928) 766-1925Why a valley-wide answer does not exist
Properties around Chino Valley draw from several different sources. Some are on Town of Chino Valley water and some on City of Prescott water. Others sit on small private systems. A great deal of the surrounding acreage is on private wells, as is effectively all of Williamson Valley and Paulden, at varying depths into different parts of the aquifer system.
USGS sampled groundwater across the Big Chino subbasin between 2011 and 2018 and found significant chemical differences between the basin-fill and carbonate aquifers. Carbonate samples ran higher in calcium, sodium, bicarbonate, fluoride and arsenic. Two wells a few miles apart, drawing from different units, can be meaningfully different water.
That is why we will not quote you a hardness figure over the phone. There is no honest single number for this valley, and sizing equipment against an invented average is how people end up with a softener that is too small to keep up or too large to regenerate efficiently.
The six things worth measuring
This is the list we would ask for on a private well here, and what each result actually decides.
| Parameter | Why it matters here | What the result decides |
|---|---|---|
| Total hardness | Drives scale in heaters, fixtures and tankless exchangers | Whether you need a softener and what size |
| Iron and manganese | Common in groundwater; fouls softener resin | Whether pre-treatment is needed before any softener |
| Arsenic | USGS found most carbonate aquifer samples above the EPA standard here | Whether you need specific removal treatment; a softener will not do it |
| Total dissolved solids and pH | Affects corrosion of pipe and fittings, and taste | Whether corrosion is a factor in fixture and pipe life |
| Bacteria | Any private well; especially after work on the wellhead | Whether disinfection is needed, and whether it is safe to drink now |
| Nitrate | Parcels with historic agricultural use or nearby septic systems | Whether there is a contamination pathway worth investigating |
The arsenic row is the one most often left off a basic test, and given the USGS findings in this subbasin it is the one we would least want to skip on a well here.
The mistake this list is designed to prevent
A softener is not a general purpose filter
Ion exchange softening removes calcium and magnesium. That is what it does, and it does it well. It is the correct answer to scale, to poor soap performance and to short water heater life.
It does not remove arsenic. It does not remove bacteria. It does not remove nitrate. It handles only limited amounts of iron before the resin fouls, which is why iron testing comes before softener sizing rather than after.
So a household that installs a softener and assumes the water is now dealt with may have solved the scale problem while leaving something more significant untouched. On a private well, nobody else is checking. That is the whole argument for testing the full list once rather than testing hardness alone.
How to actually go about it
The process is simpler and cheaper than most people expect.
Use a certified laboratory rather than a strip kit
Home test strips give a rough hardness indication and nothing else. For arsenic, nitrate and bacteria you need a laboratory result, and Arizona has certified labs that handle private well samples routinely.
Follow the sampling instructions exactly
Different parameters need different containers, and bacterial samples in particular are easy to contaminate while collecting. The lab supplies instructions; read them before you start rather than afterward.
Sample from an untreated tap if you have any existing equipment
Otherwise you are measuring what your current treatment produces, which does not tell you what the well is delivering.
Get the well log out while you are at it
Depth, construction and static water level tell you which part of the aquifer system you are drawing from, which puts the chemistry in context.
Take the results to someone before buying anything
The numbers determine the equipment. Any competent installer should be able to explain which result drove which recommendation, and if they cannot, that is informative.
When to retest
Once is not enough on a well
Groundwater is not static, and neither is your well.
- Annually for bacteria, which is the standard recommendation for any private well and the cheapest test on the list.
- After any work on the well, the pump or the wellhead, since opening the system creates a contamination pathway.
- If the water changes in taste, smell, colour or clarity, particularly if it happens suddenly.
- After a significant change in water level or pump behaviour, which can mean the well is drawing from a different depth than it was.
- Before buying a property on a well, as part of the purchase rather than after it.
- Every few years for the full chemical panel, or sooner if anything above applies.
Wells at the edges of the aquifer along Williamson Valley Road and the western side of Chino Valley have been documented going dry as regional levels decline. That is a further reason to watch both level and quality rather than testing once and filing the result.
What we do with the results
Hardness sets softener size, and size matters in both directions: too small and it cannot keep up with peak demand, too large and it regenerates inefficiently and wastes salt and water. Getting it right requires the number rather than an estimate.
Iron determines whether anything is needed ahead of the softener. Arsenic, nitrate and bacteria each point at entirely different equipment, and the honest position is that some of those are outside general plumbing work and belong with a water treatment specialist. We will tell you when that is the case.
What we will not do is quote equipment before seeing a result. Details of what we fit and how it is sized are on the treatment page, and the same advice applies whether you buy the equipment from us or not.
Questions about well testing
How much does a full test cost?
Considerably less than the equipment it might prevent you buying, and less than a single water heater replacement. Prices vary by lab and by which parameters you include, so it is worth asking two.
The bacterial test alone is inexpensive enough to do annually without thinking about it.
Can I just use my neighbour's results?
Not reliably. USGS found substantial differences between the basin-fill and carbonate aquifers in this subbasin, and two wells at different depths can be drawing from different units.
It is a reasonable indication of what to expect, but it is not a basis for sizing equipment or for deciding you do not need to check for arsenic.
What if the arsenic result comes back high?
It is worth taking seriously and it is not unusual in this subbasin, where USGS found most carbonate aquifer samples above the federal standard. Treatment options exist and they are specific to arsenic rather than general.
That is a conversation with a water treatment specialist and, if you want guidance on the standard itself, with the county or state health authorities.
Does the town test water for well owners?
Municipal systems test their own supply and publish the results. A private well is not part of that system and is not tested by anyone unless the owner arranges it.
That is the central thing to understand about being on a well here. The responsibility is genuinely yours, and it is not onerous, but it does not happen by itself.
Written and reviewed by the Chino Valley Plumbing Pros team. We publish under the company name rather than under an individual byline, because the work behind these pages is done by the crew rather than by one person.
Water supply work follows the 2024 International Plumbing Code (IPC) adopted by the Town of Chino Valley. Wells are permitted by the Arizona Department of Water Resources, and contractor licences are issued by the Arizona ROC. Licence status for any Arizona contractor, including us, can be checked on the Arizona Registrar of Contractors public licence search.
Got results and not sure what they mean?
Send us the numbers. We will tell you what they do and do not justify buying.