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Community Water System · PWS AZ0413057

Yarnell Water Improvement Association

Prescott, Arizona 86302 - drinking water served from groundwater sources to 515 people, tracked in EPA SDWIS and UCMR5.

515
People served
157
EPA violations
1
Health-based
Untested
UCMR5 result

The verdict

EPA records 157 drinking-water violations at Yarnell Water Improvement Association, 1% of them health-based - above the Arizona per-system average.

157
Total EPA violations on record
1%
Health-based (MCL / treatment failure)
515
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Yarnell Water Improvement Association

Yarnell Water Improvement Association is a private-owned community water system that delivers drinking water to 515 residents in Prescott, Arizona (Yavapai County) through 523 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 157 total violations for this system , of which 1 (1%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 126 monitoring and reporting violations are on file. The most recent violation on record dates to 2023.

The most frequently cited contaminant at this system is Chlorine, recorded in 41 violations (MR). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.

Across Arizona, EPA tracks 1,493 public water systems serving 7,322,166 people, with 228,944 cumulative violations and 15,663 health-based violations on record. About 98% of systems in the state carry at least one violation, and state-wide the average per system is 153.3 violations. Statewide, 145 of 152 UCMR5-tested systems have reported PFAS detections (95.4%).

Yarnell Water Improvement Association's 157 violations sit above the Arizona average.

All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.

Population Served
515
Total Violations
157
Health-Based Violations
1
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Private
Connections
523
County
Yavapai
School/Daycare
No
MCL Violations
1
Monitoring Violations
126
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Chlorine MR 41 2022
Coliform (TCR) MR 16 2014
Consumer Confidence Rule Other 15 2023
Lead and Copper Rule MR 7 2021
Total Haloacetic Acids (HAA5) MR 3 2008
Revised Total Coliform Rule RPT 3 2022
Revised Total Coliform Rule MON 3 2016
TTHM MR 3 2008
1,2-Dichloroethane MR 2 2011
1,1,1-Trichloroethane MR 2 2011
Carbon tetrachloride MR 2 2011
1,2-Dichloropropane MR 2 2011
Trichloroethylene MR 2 2011
1,1,2-Trichloroethane MR 2 2011
Benzene MR 2 2011
Styrene MR 2 2011
Nitrate MR 2 1999
1,2,4-Trichlorobenzene MR 2 2011
cis-1,2-Dichloroethylene MR 2 2011
Xylenes, Total MR 2 2011
DICHLOROMETHANE MR 2 2011
p-Dichlorobenzene MR 2 2011
Tetrachloroethylene MR 2 2011
CHLOROBENZENE MR 2 2011
Public Notice Other 2 2020
o-Dichlorobenzene MR 2 2011
Gross Alpha, Excl. Radon and U MR 2 1988
trans-1,2-Dichloroethylene MR 2 2011
Toluene MR 2 2011
1,1-Dichloroethylene MR 2 2011

Verify This Water System

The figures above are aggregated from EPA's public databases. To verify the underlying records, or to file a complaint, request a Consumer Confidence Report, or check current monitoring status, go directly to the federal and state regulators that enforce the Safe Drinking Water Act for Yarnell Water Improvement Association.

Federal Source of Truth

EPA SDWIS, Federal Reports

EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:

View PWS ID AZ0413057 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

Arizona Drinking Water Authority

Arizona DEQ, Drinking Water Program is the primacy agency that licenses and inspects Yarnell Water Improvement Association under EPA-delegated authority.

Open AZ regulator portal

Source: Arizona DEQ, Drinking Water Program

Violation Timeline

Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.

Year (latest) Contaminant Category Count EPA Record
2023 Consumer Confidence Rule Other 15 SDWIS / AZ0413057 / 7000
2022 Chlorine MR 41 SDWIS / AZ0413057 / 0999
2022 Revised Total Coliform Rule RPT 3 SDWIS / AZ0413057 / 8000
2021 Lead and Copper Rule MR 7 SDWIS / AZ0413057 / 5000
2020 Public Notice Other 2 SDWIS / AZ0413057 / 7500
2016 Revised Total Coliform Rule MON 3 SDWIS / AZ0413057 / 8000
2014 Coliform (TCR) MR 16 SDWIS / AZ0413057 / 3100
2011 1,2-Dichloroethane MR 2 SDWIS / AZ0413057 / 2980
2011 1,1,1-Trichloroethane MR 2 SDWIS / AZ0413057 / 2981
2011 Carbon tetrachloride MR 2 SDWIS / AZ0413057 / 2982
2011 1,2-Dichloropropane MR 2 SDWIS / AZ0413057 / 2983
2011 Trichloroethylene MR 2 SDWIS / AZ0413057 / 2984
2011 1,1,2-Trichloroethane MR 2 SDWIS / AZ0413057 / 2985
2011 Benzene MR 2 SDWIS / AZ0413057 / 2990
2011 Styrene MR 2 SDWIS / AZ0413057 / 2996

How Yarnell Water Improvement Association Compares

Cross-reference this system's record against state averages and the federal MCL framework for context.

Metric Yarnell Water Improvement Association Arizona avg Federal benchmark
Total violations 157 153.3 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 1 10.5 Indicates a contaminant exceeded a federal MCL
PFAS detection None 95.4% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 515 4,904 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 1,493 regulated public water systems in Arizona.

Federal MCL reference, Safe Drinking Water Act thresholds ▼
Contaminant Federal MCL / Action Level Note
Lead 0 mg/L (Action Level: 0.015 mg/L) Lead and Copper Rule treatment technique
Arsenic 0.010 mg/L (10 ppb) Health-based MCL since 2006
Total Coliform Treatment technique (RTCR) Indicator organism, monitoring trigger
PFOA / PFOS (PFAS) 4.0 ppt each (final 2024 rule) Compliance deadline 2029 (EPA proposed extending to 2031, not yet final as of May 2026)
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is Yarnell Water Improvement Association water safe to drink? ▼
Yarnell Water Improvement Association (PWS ID: AZ0413057) has 157 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 515 people using Groundwater sources.
How many people does Yarnell Water Improvement Association serve? ▼
Yarnell Water Improvement Association serves 515 people in Prescott, Arizona. It is a Private-owned system using Groundwater water sources with 523 service connections.
What type of violations does Yarnell Water Improvement Association have? ▼
Yarnell Water Improvement Association has 157 total violations: 1 health-based violations (MCL exceedances or treatment failures), 126 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Yarnell Water Improvement Association water? ▼
No PFAS testing data is available for Yarnell Water Improvement Association under the EPA's UCMR5 monitoring program.
What water source does Yarnell Water Improvement Association use? ▼
Yarnell Water Improvement Association uses Groundwater as its primary water source. It is classified as a Community Water System (CWS), serving residential populations year-round.
Where does this data come from? ▼
All data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS tracks compliance for all public water systems regulated under the Safe Drinking Water Act.
Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025. This data is provided for informational purposes only.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.