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Transient Non-Community Water System · PWS AZ0412302

AZ State Pks Patagonia Lake

Nogales, Arizona 85621 - drinking water served from groundwater sources to 564 people, tracked in EPA SDWIS and UCMR5.

564
People served
31
EPA violations
1
Health-based
Untested
UCMR5 result

The verdict

EPA records 31 drinking-water violations at AZ State Pks Patagonia Lake, 3% of them health-based - below the Arizona per-system average.

31
Total EPA violations on record
3%
Health-based (MCL / treatment failure)
564
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: AZ State Pks Patagonia Lake

AZ State Pks Patagonia Lake is a state-owned transient non-community water system that delivers drinking water to 564 residents in Nogales, Arizona (Santa Cruz County) through 140 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 31 total violations for this system , of which 1 (3%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 27 monitoring and reporting violations are on file. The most recent violation on record dates to 2020.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 12 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%).

AZ State Pks Patagonia Lake's 31 violations sit below 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
564
Total Violations
31
Health-Based Violations
1
Water Source
Groundwater

System Details

System Type
Transient Non-Community
Owner Type
State
Connections
140
County
Santa Cruz
School/Daycare
No
MCL Violations
1
Monitoring Violations
27
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MR 12 2010
Nitrate MR 8 2013
Revised Total Coliform Rule RPT 2 2020
Coliform (TCR) MCL 1 2006
Selenium MR 1 1988
Cadmium MR 1 1988
Fluoride MR 1 1988
Arsenic MR 1 1985
Chromium MR 1 1988
Mercury MR 1 1988
Barium MR 1 1988

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 AZ State Pks Patagonia Lake.

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 AZ0412302 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 AZ State Pks Patagonia Lake 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
2020 Revised Total Coliform Rule RPT 2 SDWIS / AZ0412302 / 8000
2013 Nitrate MR 8 SDWIS / AZ0412302 / 1040
2010 Coliform (TCR) MR 12 SDWIS / AZ0412302 / 3100
2006 Coliform (TCR) MCL 1 SDWIS / AZ0412302 / 3100
1988 Selenium MR 1 SDWIS / AZ0412302 / 1045
1988 Cadmium MR 1 SDWIS / AZ0412302 / 1015
1988 Fluoride MR 1 SDWIS / AZ0412302 / 1025
1988 Chromium MR 1 SDWIS / AZ0412302 / 1020
1988 Mercury MR 1 SDWIS / AZ0412302 / 1035
1988 Barium MR 1 SDWIS / AZ0412302 / 1010
1985 Arsenic MR 1 SDWIS / AZ0412302 / 1005

How AZ State Pks Patagonia Lake Compares

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

Metric AZ State Pks Patagonia Lake Arizona avg Federal benchmark
Total violations 31 153.3 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 564 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 AZ State Pks Patagonia Lake water safe to drink? ▼
AZ State Pks Patagonia Lake (PWS ID: AZ0412302) has 31 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 564 people using Groundwater sources.
How many people does AZ State Pks Patagonia Lake serve? ▼
AZ State Pks Patagonia Lake serves 564 people in Nogales, Arizona. It is a State-owned system using Groundwater water sources with 140 service connections.
What type of violations does AZ State Pks Patagonia Lake have? ▼
AZ State Pks Patagonia Lake has 31 total violations: 1 health-based violations (MCL exceedances or treatment failures), 27 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in AZ State Pks Patagonia Lake water? ▼
No PFAS testing data is available for AZ State Pks Patagonia Lake under the EPA's UCMR5 monitoring program.
What water source does AZ State Pks Patagonia Lake use? ▼
AZ State Pks Patagonia Lake uses Groundwater as its primary water source. It is classified as a Transient Non-Community Water System, serving transient populations.
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.