F0/100

NOGALES CITY OF — Water Quality Report 2026

Serving 22,000 people · Arizona

Water Source

Groundwater

County

—

System ID

AZ0412004

Violations

1226

Contaminant Test Results

EPA Violation History

Violations (last 5yr)

Unresolved

Health-Related

TIER 3Unresolved

Failed Level 2 Assessment under Revised Total Coliform Rule

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: July 1, 2025 – July 31, 2025Rule: Stage 1 DBPRVerify on EPA.gov

TIER 3Resolved

Disinfection byproduct treatment technique failure

When: December 20, 2024 – February 6, 2025Rule: Ground Water RuleEnforcement: Resolving — corrective action underway

TIER 3Resolved

Reporting violation

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: October 17, 2024Rule: Ground Water RuleEnforcement: Formal — state order issued

TIER 2Resolved

Treatment technique violation

When: October 17, 2024Rule: Ground Water RuleEnforcement: Formal — state order issued

TIER 3Resolved

Failed Level 2 Assessment under Revised Total Coliform Rule

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: October 1, 2024 – December 31, 2024Rule: Stage 2 DBPREnforcement: Resolving — corrective action underway

TIER 3Resolved

Exceeded the MCL for disinfection byproducts

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: October 1, 2024 – December 31, 2024Enforcement: Resolving — corrective action underway

TIER 3Resolved

Failed Level 2 Assessment under Revised Total Coliform Rule

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: October 1, 2024 – December 31, 2024Rule: Stage 2 DBPREnforcement: Resolving — corrective action underway

TIER 3Resolved

Disinfection byproduct treatment technique failure

When: April 28, 2024 – June 19, 2024Rule: Ground Water RuleEnforcement: Resolving — corrective action underway

TIER 3Resolved

Exceeded the MCL for disinfection byproducts

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: October 1, 2023 – December 31, 2023Enforcement: Resolving — corrective action underway

TIER 3Resolved

Failed Level 2 Assessment under Revised Total Coliform Rule

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: October 1, 2023 – December 31, 2023Rule: Stage 2 DBPREnforcement: Resolving — corrective action underway

TIER 3Resolved

Failed Level 2 Assessment under Revised Total Coliform Rule

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: October 1, 2023 – December 31, 2023Rule: Stage 2 DBPREnforcement: Resolving — corrective action underway

TIER 3Resolved

Monitoring violation

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: July 1, 2023 – August 18, 2023Rule: Total Coliform RuleEnforcement: Resolving — corrective action underway

TIER 3Resolved

Exceeded the MCL for disinfection byproducts

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: July 1, 2023 – September 30, 2023Enforcement: Resolving — corrective action underway

TIER 3Resolved

Failed Level 2 Assessment under Revised Total Coliform Rule

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: April 1, 2023 – June 30, 2023Rule: Stage 1 DBPREnforcement: Resolving — corrective action underway

TIER 3Resolved

Exceeded the MCL for disinfection byproducts

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: January 1, 2023 – March 31, 2023Enforcement: Resolving — corrective action underway

TIER 3Resolved

Exceeded the MCL for disinfection byproducts

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: January 1, 2023 – December 31, 2023Enforcement: Resolving — corrective action underway

TIER 3Resolved

Exceeded the MCL for disinfection byproducts

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: January 1, 2023 – December 31, 2023Enforcement: Resolving — corrective action underway

TIER 2Resolved

Violation related to Consumer Confidence Report

When: November 15, 2021 – March 2, 2022Rule: Consumer Confidence RuleEnforcement: Resolving — corrective action underway

Understanding violation severity

Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.

Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly

Frequently Asked Questions About NOGALES CITY OF

Is NOGALES CITY OF water safe to drink?

NOGALES CITY OF water receives a grade of F (0/100), which is considered failing. 0 contaminant(s) exceed EPA legal limits and 1226 violation(s) are on record. Customers may want to consider using a water filter.

What contaminants has NOGALES CITY OF detected?

66 contaminants were tested in NOGALES CITY OF's water. No contaminants exceed EPA legal limits or health goals, indicating good water quality management.

Does NOGALES CITY OF have any EPA violations?

Yes, NOGALES CITY OF has 1226 EPA violation(s) on record, with the most recent in 2025. Violation types include MR, Other, RPT. 23 are health-based violations.

How many people does NOGALES CITY OF serve?

NOGALES CITY OF serves approximately 22,000 people, Arizona. The system provides water to 1 community: Nogales.

What type of water does NOGALES CITY OF provide?

NOGALES CITY OF sources its water from groundwater. Groundwater is pumped from underground aquifers, which often provides natural filtration. The utility's system ID is AZ0412004.

How does NOGALES CITY OF compare to other utilities in Arizona?

NOGALES CITY OF scores 0/100 with a grade of F (failing). This score suggests significant water quality concerns relative to other utilities. Visit our Arizona state page for a full comparison of water systems.

Cities Served

Nogales