Well water in Mohave County, Arizona

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Testing recommended

tested well samples in Mohave County exceeded the EPA limit for arsenic (10 ug/L), based on public data from USGS Water Quality Portal.

The strongest signal is PFOA: 31% of 13 local samples were above the limit, too few samples to carry the headline but first on the test list below.

9,994 test results across 14 contaminants from at least 795 wells, 1943 to 2026; fluoride has the most at 1,373. Data refreshed September 15, 2026.

Compiled by Nick at Well Water Nerd from public records. How these pages are built

An estimated 8,270 people in Mohave County get their drinking water from a private well, per USGS 2015 county water use. That is about 4% of residents.

Separately, the USGS national arsenic model estimates that 6% of the 8,270 people on private wells in Mohave County draw water above 10 ug/L (the model's range is 5% to 7%), from geology and well depth rather than local tests.

What individual samples found

Each row summarizes every public sample for that contaminant inside Mohave County. Above limit means above the EPA maximum contaminant level; where EPA has no enforceable limit, the row shows a health guideline or nuisance level instead.

Contaminant	Above limit	Samples	Detected	Median	Highest	Limit
PFOA 2024	31%	13	46%	0	63.8	4 ng/L EPA limit
Arsenic 1975 to 2025	17%	829	53%	0.68	300	10 ug/L EPA limit
Nitrate 1944 to 2026	13%	1,184	86%	2.1	190	10 mg/L EPA limit
Radium (226 + 228) 1982 to 2013	6%	130	36%	0	33	5 pCi/L EPA limit
Fluoride 1943 to 2024	5%	1,373	98%	0.89	49	4 mg/L EPA limit
Lead 1975 to 2022	2%	647	17%	0	100	15 ug/L EPA limit
Copper 1975 to 2022	0%	639	23%	0	0.415	1.3 mg/L EPA limit
Uranium 1980 to 2018	0%	38	100%	6.29	21.1	30 ug/L EPA limit
Chloride 1943 to 2026	no limit	1,342	100%	75.8	4,080	250 mg/L nuisance level
Iron 1962 to 2026	no limit	1,276	53%	3.55	35,200	300 ug/L nuisance level
Sodium 1961 to 2024	no limit	1,241	100%	94	2,074	20 mg/L health guideline
Manganese 1968 to 2026	no limit	1,182	51%	0	8,360	300 ug/L health guideline
Radon 2000 to 2013	no limit	97	100%	286	4,839	2,000 pCi/L health guideline

Sampled fewer than 10 times, too few to summarize: E. coli (3).

Over time

Share of samples above the limit by period. A cell needs ten samples to show; a comparison needs twenty in each period. Later periods sample fewer wells, and often the ones already known to have a problem.

Contaminant	before 2000	2000s	2010s	2020s
Fluoride	5%1,011 samples	7%345 samples	0%16 samples	n/a
Nitrate	6%728 samples	18%268 samples	16%55 samples	40%133 samples
Arsenic	17%391 samples	21%330 samples	20%15 samples	0%93 samples
Lead	2%329 samples	1%274 samples	0%15 samples	0%29 samples
Copper	0%321 samples	0%274 samples	0%15 samples	0%29 samples
Radium (226 + 228)	10%48 samples	4%74 samples	n/a	n/a

Nitrate above the limit in Mohave County rose from 16% of 55 samples in the 2010s to 40% of 133 in the 2020s.

Arsenic above the limit in Mohave County fell from 21% of 330 samples in the 2000s to 0% of 93 in the 2020s.

Radium (226 + 228) above the limit in Mohave County fell from 10% of 48 samples before 2000 to 4% of 74 in the 2000s.

Fluoride, lead, copper have held within a few points between the two most recent periods with enough samples.

Closer than the county

See the sampled wells near your address

The same records, drawn around one point: which wells within a few miles were sampled and what they found, how deep the wells next to you were drilled, and any leaking tank or cleanup site within a mile.

Check my address

What this means

The contaminants most often above their limit here are pfoa (31% of 13 samples), arsenic (17% of 829 samples), and nitrate (13% of 1,184 samples). A well next door can differ sharply from yours because bedrock fractures, well depth and plumbing all matter, so these rates describe the area, not your tap.

Chloride, Iron, and Manganese are widespread in local groundwater. They are mainly a staining and taste problem, but high manganese also carries a health advisory for infants.

What to test for in Mohave County

1
PFOA
31% of 13 local samples were above the limit.
2
Arsenic
17% of 829 local samples were above the limit.
3
Nitrate
13% of 1,184 local samples were above the limit.
4
Radium (226 + 228)
6% of 130 local samples were above the limit.
5
Fluoride
5% of 1,373 local samples were above the limit.
6
Lead
2% of 647 local samples were above the limit.
7
Coliform bacteria
Recommended for every private well, every year.
8
Volatile organic compounds (VOCs)
206 leaking underground storage tank sites on record locally.

Test your Mohave County well for PFOA, arsenic and nitrate

Certified lab analysis of your own tap water, bottles and prepaid return shipping included. The Essential well panel covers arsenic, uranium, nitrate, lead, copper, manganese, iron, sodium and bacteria; radon and PFAS are add-ons.

Order the Tap Score well water test kit, from $209 Already tested? Upload the report

Just want bacteria checked first? Tap Score coliform and E. coli test, $99. Coliform and E. coli are the tests every well needs every year.

Want a quick look before paying for a lab? Home well water test strips on Amazon check hardness, iron, pH and nitrate in minutes. They are a screen, not a result: arsenic, bacteria, uranium and PFAS need a certified lab.

Affiliate links: the merchant pays us a commission and the price is the same for you. It does not change what the data above says. As an Amazon Associate we earn from qualifying purchases.

Where to get a well tested in Arizona: certified labs, state programs and prices.

Already have results back? Get your lab report read against the Mohave County numbers, $29. Every line explained, ranked by what matters, with the fix for each.

Wells in Mohave County

10,034 domestic wells in Mohave County are on record with the state since 1970. the typical well is 251 feet deep (one in ten goes past 780 feet).

In a typical Mohave County well, the median yield is 15 gallons per minute, 5% of wells yield under 3 gallons per minute and usually need a storage tank.

746

1970s

1,158

1980s

1,264

1990s

1,948

2000s

674

2010s

665

2020s

Find your own well's report

The state keeps the driller's report for most wells drilled since 1984. It tells you how deep your well is, where bedrock starts, and how much water it makes, which decides what treatment can work.

Open ADWR Wells55 registry and choose Water Well.
The record lists depth, water level, casing depth and the tested rate, plus a link to the drilling log.

Arizona has registered wells since 1980; earlier wells often have no record.

The rock under Mohave County

Not a principal aquifer

The USGS map places this area outside any principal aquifer, which usually means wells here draw from fractured bedrock or thin local deposits rather than a large regional aquifer. Bedrock wells of that kind are where arsenic, radon and uranium turn up, and yields vary from well to well.

Classification from the USGS Principal Aquifers of the United States (national map, 2003 edition, GIS release 2015), read at the county centroid. A single well can sit in a different unit, especially near a boundary.

Official help in Arizona

Two places to start that are not selling anything: the state program that answers private well questions, and its list of labs certified to run drinking water tests. A certified lab is the difference between a result you can act on and a number.

Well Water, ADHS
Licensed Commercial Drinking Water Laboratories, ADHS

Contamination sources on record in Mohave County

ADEQ records 206 leaking underground storage tank sites in Mohave County, among 210 regulated sites in total. Groundwater does not follow property lines, so a well within a few hundred feet of one of these is worth testing for what that site could release.

206: leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
4: lined landfills and transfer facilities

Treatment that fits the local profile

PFOA

Granular activated carbon whole-house; Point-of-use reverse osmosis; Anion exchange

Arsenic

Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange

Nitrate

Point-of-use reverse osmosis; Anion exchange; Distillation

Radium (226 + 228)

Water softener (cation exchange); Point-of-use reverse osmosis

Fluoride

Point-of-use reverse osmosis; Activated alumina; Distillation

Systems we would look at first

Some links below are affiliate links. If you buy through one, the merchant pays us a commission at no extra cost to you. It does not change which products we list or what the data says.

For PFOA

Under-sink reverse osmosis system

under-sink or countertop, about $300

Look for NSF/ANSI 58 certification listing the contaminant you need removed.

For PFOA

Whole-house PFAS carbon system

whole-house, at the point of entry, about $3,000

Granular activated carbon certified to NSF/ANSI 53 for PFOA and PFOS; replace media on schedule.

For PFOA

Aquasana SmartFlow reverse osmosis

under-sink or countertop, about $225

Certified to NSF/ANSI 58 and 53 to reduce arsenic (96%, pentavalent), fluoride (90%), lead (99%), nitrate, nitrite and PFOA/PFOS at the kitchen tap, with a remineralizer.

For arsenic

Whole-house arsenic and uranium filter

whole-house, at the point of entry, about $2,500

Adsorptive iron-based media; sized to your well yield.

For lead

Aquasana Claryum 3-Stage under-sink filter

under-sink or countertop, about $175

Certified to NSF/ANSI 53 to reduce 99% of lead and 99.7% of PFOA and PFOS at the tap. Not a fix for arsenic, nitrate or bacteria.

For lead

Acid neutralizing filter

whole-house, at the point of entry, about $1,200

Raises pH so plumbing stops leaching lead and copper.

Free, no obligation

Get on the list for a free in-home water test in Mohave County

No water treatment company serves Mohave County through Well Water Nerd yet. We are signing licensed companies on county by county: they test at your tap for free, walk you through the numbers, and quote treatment only if something needs fixing. Leave your details and you are first in line. Nothing is shared until a company joins for Mohave County, and you get an email naming it first.

Common questions

How deep are wells in Mohave County?

The typical domestic well in Mohave County is 251 feet deep, based on 10,034 wells reported to the state since 1970. One in ten is deeper than 780 feet.

Is there arsenic in well water in Mohave County?

Arsenic was detected in 53% of 829 public well samples in Mohave County, and 17% were above the EPA limit of 10 ug/L. Arsenic has no taste or smell; a lab test is the only way to know your level.

How high is radon in well water in Mohave County?

The median radon level across 97 public samples in Mohave County was 286 pCi/L, with a high of 4,839 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.

How often should I test a private well in Mohave County?

Test for bacteria and nitrate every year. Test once for arsenic, uranium, radon, fluoride, manganese and PFAS, then again every three to five years or after any change in taste, color, or plumbing.

Counties near Mohave County

Closest first. Groundwater does not stop at a line on a map, so the next county over is a fair second opinion.

Want the numbers themselves? Download the Arizona dataset as CSV, every county and town, with the sources named.

Sources

USGS Water Quality Portal: 9,994 samples in Mohave County. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
USGS national arsenic model (Ayotte 2017): estimated share of 8,270 people on private wells in Mohave County above 10 ug/L of arsenic, from geology, well depth and land use. County estimates of domestic well users with arsenic above 10 ug/L from the USGS national logistic regression model (Ayotte, Medalie and Qi, 2017), with private well population from the USGS 2015 county water-use compilation (Dieter and others, 2018). Retrieved September 15, 2026.
Arizona ADWR well registry (Wells55): 15,727 well records in Mohave County, 10,034 domestic. Registered wells from the Arizona Department of Water Resources Wells55 registry. Only aggregates are shown; owner names and addresses are never stored. Retrieved September 18, 2026.
ADEQ regulated sites: 210 regulated sites located in Mohave County. Leaking underground storage tank sites and municipal landfills from the Arizona Department of Environmental Quality. Retrieved September 18, 2026.

Non-detects count as samples and are treated as zero when computing medians. Exactly at the limit counts as not above it. A sample belongs to the town containing the well's reported coordinates.