Is Dewey-Humboldt, AZ tap water safe?
The short answer
2 of the 3 utilities serving Dewey-Humboldt have a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and CDC’s records: Humboldt Water System and White Horse Ranch Owners Association.
Town of Prescott Valley, which serves the most people here, has 1 result above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 24.7 ppb, above EPA’s health benchmark. Health goals are stricter than legal limits and are not enforced.
A town can be served by more than one utility, and some homes are on private wells. The name on your water bill tells you which is yours, and your ZIP code narrows it down. They are listed by how many people each serves in Dewey-Humboldt’s ZIP codes, from EPA’s estimates.
- Open report
Town of Prescott Valley
Arizona · serves 57,048 people · about 370 in Dewey-Humboldt
1 result above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 24.7 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Humboldt Water System
Arizona · serves 830 people · about 330 in Dewey-Humboldt
1 result above the legal limit and 1 result above the health goal. The worst: Nitrate at 8.8 ppm, above the legal limit.
1 health-based violation since 2016
- Open report
White Horse Ranch Owners Association
Arizona · serves 292 people · under 100 in Dewey-Humboldt
1 result above the legal limit and 2 results above the health goal. The worst: Nitrate at 15.7 ppm, above the legal limit.
37 health-based violations since 2016
What handles it
Each of these is certified, on a certifier’s listing, for a result above a line in Town of Prescott Valley’s water, which serves the most people here. Another utility’s report names what handles its own results.
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Countertop reverse osmosis
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 4, 2026
Certified for: Arsenic
Aquasana SmartFlow Reverse Osmosis (AQ-SFRO2)
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic
Brondell Capella RC250 Reverse Osmosis System
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic
Water testing near Dewey-Humboldt
The 3 labs Arizona certifies closest to Dewey-Humboldt, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
Bradshaw Mountain Environmental Inc.
Prescott Valley, AZ · about 9 miles
Inner Basin Environmental, LLC
Flagstaff, AZ · about 63 miles
Nortest Analytical
Flagstaff, AZ · about 63 miles
Which ZIP codes are in Dewey-Humboldt: Census 2020 relationship files. Which utilities serve them, and how many people: EPA SDWIS and EPA’s service area map. Each utility’s results: EPA UCMR 5, EPA SDWIS, and EPA’s and the state’s compliance monitoring, as its report lists them. How they are measured: methodology. Certified labs: Arizona Department of Health Services, Arizona certified commercial drinking water laboratories; distances from the Census 2020 ZIP code tabulation area gazetteer.
Near Dewey-Humboldt
Other towns in Yavapai County with a page of their own.
What to do next
- Read Town of Prescott Valley’s full reportEvery result with its dates, the violations, and the certification claim that handles each finding.Open the report
- About LithiumWhat it does to health, where it comes from, and the certification claim that addresses it.About Lithium
- On a private well?No utility tests a well. A certified lab test is the first step.How to test well water