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C - Oasis Park

What EPA’s and CDC’s records show in this utility’s water: nitrate, arsenic and other regulated chemicals; lead and copper; and violations since 2016, with the certification that handles each result.

Serves
54 people
Connections
27
Water source
Groundwater
Based in
Cottonwood, AZ
County
Yavapai
Owner
Public and private
The ZIP code it serves

86326

The short answer

1 result is above EPA’s legal limit, and 2 more are above the health goal. The worst: Nitrate, above the legal limit. 1 health-based violation since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2009 to 2025.

Nitrate and arsenic: Arizona’s yearly averages per water system, as CDC’s Environmental Public Health Tracking Network publishes them, 2020 to 2023, with EPA’s 2012 to 2019 file for earlier years.

Fluoride and chromium (total): EPA’s compliance monitoring file, samples taken from Sept. 26, 2013 to Sept. 26, 2013. Newer results are in the utility’s annual water quality report.

Above the legal limit1

Nitrate

Comes from the source

Above the legal limit

1.8ppm

Highest yearly average, 2020 to 2023

Averaged by year, the highest was 1.8 ppm, in 2023, below EPA’s legal limit of 10 ppm. That was also the latest year on file. EPA judges this limit at each sampling point, and recorded a violation for nitrate at this utility in 2026. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 4.1 ppm, in 2012.

What handles it

  • NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
  • NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”

Above the health goal2

Lead

Comes from pipes, often your own

Above the health goal

7.0ppb

90th percentile, 2023 to 2025

In the latest period, 9 in 10 homes sampled were at or below 7.0 ppb, below EPA’s action level of 15 ppb. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.

What handles it

Arsenic

Comes from the source

Above the health goal

3.2ppb

Highest yearly average, 2022

Averaged by year, the highest was 3.2 ppb, in 2022: below EPA’s legal limit of 10 ppb, but above its health goal of zero. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 3.5 ppb, in 2013.

What handles it

  • NSF/ANSI 58 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
  • NSF/ANSI 53 look for “Arsenic (Pentavalent)<=50 ppb Reduction”

Below EPA’s limits2

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.15ppm

Highest yearly average, 2013

Averaged by year, the highest was 0.15 ppm, in 2013, below EPA’s legal limit of 4.0 ppm. That is the only year on file.

What handles it

Chromium (total)

Comes from the source

Below EPA’s limits

3.2ppb

Highest yearly average, 2013

Averaged by year, the highest was 3.2 ppb, in 2013, below EPA’s legal limit of 100 ppb. That is the only year on file.

What handles it

What handles it

A certification covers specific claims, not a whole standard. Look for these claims on the certifier’s listing, not the box. Wording varies a little: NSF writes “Lead Reduction,” WQA just “Lead.”

  • NSF/ANSI 53

    Claims: Nitrate/Nitrite (30 ppm challenge), Lead Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Nitrate, Lead, Arsenic

    Other certifiers’ wording: Arsenic (III) (50 ppb influent level)

  • NSF/ANSI 58

    Claims: Nitrate/Nitrite Reduction, Lead Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Nitrate, Lead, Arsenic

    Other certifiers’ wording: Nitrate; Arsenic (Pentavalent)<=300 ppb Reduction; Arsenic (V) (300 ppb influent level)

At the tap, or for the whole house?

Lead and copper usually come from pipes and fixtures inside or near your home. A whole-house system sits where water enters, so it cannot catch what your own plumbing adds after it. For those, the filter that counts is the one at the tap. How whole-house systems compare.

Filters with those claims on a certifier’s listing

Disclosure: TapBuff earns a commission if you buy through some links on this page. It does not change which standard or filter we name. As an Amazon Associate, TapBuff earns from qualifying purchases. How TapBuff makes money

Compare five-year costs

The best reverse osmosis systems, ranked

The best water filters for lead, ranked

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJan. 1, 2026 to Dec. 31, 202621 MG/LResolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record.

What this report can’t tell you

  • Everything else. Nitrate and arsenic results here are Arizona’s yearly averages as CDC publishes them, from 2020 on, with EPA’s national file for 2012 to 2019. Fluoride and chromium (total) come from EPA’s file alone, which ends in 2019. C - Oasis Park’s own annual report, which it must send you every year, has newer results for those and the contaminants this page does not show.

  • Your own plumbing. Lead results are the 90th percentile across homes the utility samples. Your home’s service line, solder and fixtures decide yours. A certified lab test is the only way to know.

  • What it means for your health. This page reports what the records show and EPA’s limits and goals; it is not medical advice. If you are worried about a health effect, talk to a doctor or your local health department.

  • Anything after the latest data. SDWIS data is from 2026 Q3; UCMR 5 didn’t sample this utility; CDC’s yearly averages for Arizona cover 2020 to 2023; EPA’s compliance samples are from Sept. 26, 2013 to Sept. 26, 2013.

Testing your own tap

C - Oasis Park’s results are for the water it sends out. What your own service line, solder and fixtures add shows up only in a test of your tap, by a lab Arizona certifies.

The 3 labs Arizona certifies closest to the area C - Oasis Park serves, 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 12 miles

    (928) 778-4510

  • Inner Basin Environmental, LLC

    Flagstaff, AZ · about 48 miles

    (928) 440-5168

  • Nortest Analytical

    Flagstaff, AZ · about 48 miles

    (928) 774-2312

All 49 certified labs for Arizona

Sources

PWSID AZ0413423. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Yavapai County

All Arizona utilities

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