F0/100

San Carlos Tap Water Quality: Is It Safe to Drink? (2026 Report)

Serving 11,638 residents · Arizona

What's In San Carlos's Tap Water?

Choose your water utility(2 serving San Carlos)

Contaminants Tested

Exceed EPA Limits

Above EPA Goals

1 contaminant above EPA health goals

Contaminant	Detected	Limit (MCL)	Goal (MCLG)	Status
Lead (90th percentile)	0.005 mg/L	0.015 mg/L	0 mg/L	Above Goal

EPA Violation History

107

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 – September 30, 2025Rule: Stage 1 DBPRVerify on EPA.gov

TIER 3Unresolved

Reporting Violation

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

When: November 16, 2024Rule: Ground Water RuleEnforcement: Informal — resolved cooperativelyVerify on EPA.gov

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: July 1, 2024 – September 30, 2024Rule: 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: April 1, 2024 – June 30, 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: April 1, 2024 – June 30, 2024Rule: 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: April 1, 2024 – June 30, 2024Enforcement: 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: April 1, 2024 – June 30, 2024Enforcement: Resolving — corrective action underway

TIER 3Resolved

Disinfection byproduct treatment technique failure

When: March 1, 2024 – June 10, 2025Rule: Ground Water RuleEnforcement: 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: March 1, 2024 – March 31, 2024Rule: 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: January 1, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: Resolving — corrective action underway

TIER 3Resolved

Disinfection byproduct treatment technique failure

When: January 1, 2024 – June 10, 2025Rule: Ground Water RuleEnforcement: 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: January 1, 2024 – March 31, 2024Rule: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Enforcement: 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, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Rule: Revised Total Coliform RuleEnforcement: 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: January 1, 2024 – January 31, 2024Rule: 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: January 1, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Rule: Revised 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: January 1, 2024 – March 31, 2024Enforcement: 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, 2024 – March 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, 2023 – December 31, 2023Rule: Stage 1 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: July 1, 2023 – September 30, 2023Rule: Stage 1 DBPREnforcement: Resolving — corrective action underway

TIER 1 — URGENTResolved

Maximum Contaminant Level Violation

When: July 1, 2023 – July 31, 2023Rule: Total Coliform RuleEnforcement: Resolving — corrective action underway

TIER 1 — URGENTResolved

Maximum Contaminant Level Violation

When: June 1, 2023 – June 30, 2023Rule: Total Coliform RuleEnforcement: Resolving — corrective action underway

TIER 2Resolved

Monitoring violation

When: May 13, 2023 – August 14, 2023Rule: Total Coliform RuleEnforcement: 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: May 1, 2023 – May 31, 2023Rule: Total Coliform RuleEnforcement: Resolving — corrective action underway

TIER 1 — URGENTResolved

Maximum Contaminant Level Violation

When: May 1, 2023 – May 31, 2023Rule: Total Coliform RuleEnforcement: 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

Disinfection byproduct treatment technique failure

When: April 1, 2023 – July 1, 2024Rule: Ground Water RuleEnforcement: 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: April 1, 2023 – April 30, 2023Rule: Total Coliform RuleEnforcement: Resolving — corrective action underway

TIER 2Resolved

Violation related to Consumer Confidence Report

When: March 4, 2023 – April 15, 2024Rule: Consumer Confidence RuleEnforcement: Formal — state order issued

TIER 2Resolved

Violation related to Consumer Confidence Report

When: March 4, 2023 – April 15, 2024Rule: Consumer Confidence RuleEnforcement: Formal — state order issued

TIER 2Resolved

Violation related to Consumer Confidence Report

When: March 4, 2023 – December 8, 2023Rule: Consumer Confidence RuleEnforcement: Formal — state order issued

TIER 2Resolved

Violation related to Consumer Confidence Report

When: March 4, 2023 – July 13, 2025Rule: Consumer Confidence RuleEnforcement: Formal — state order issued

TIER 2Resolved

Violation related to Consumer Confidence Report

When: March 4, 2023 – June 10, 2025Rule: Consumer Confidence RuleEnforcement: Formal — state order issued

TIER 3Resolved

Disinfection byproduct treatment technique failure

When: March 4, 2023 – July 1, 2024Rule: Ground Water RuleEnforcement: Resolving — corrective action underway

TIER 3Resolved

Disinfection byproduct treatment technique failure

When: March 4, 2023 – July 1, 2024Rule: Ground Water RuleEnforcement: Resolving — corrective action underway

TIER 3Resolved

Disinfection byproduct treatment technique failure

When: March 4, 2023 – July 1, 2024Rule: Ground Water RuleEnforcement: Resolving — corrective action underway

TIER 3Resolved

Disinfection byproduct treatment technique failure

When: March 4, 2023 – July 1, 2024Rule: Ground Water RuleEnforcement: Resolving — corrective action underway

TIER 3Resolved

Disinfection byproduct treatment technique failure

When: March 4, 2023 – July 1, 2024Rule: Ground Water RuleEnforcement: Resolving — corrective action underway

TIER 2Resolved

Violation related to Consumer Confidence Report

When: March 4, 2023 – August 2, 2023Rule: Consumer Confidence RuleEnforcement: Formal — state order issued

TIER 3Resolved

Disinfection byproduct treatment technique failure

When: March 4, 2023 – July 1, 2024Rule: Ground Water RuleEnforcement: 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: February 1, 2023 – May 24, 2023Rule: Total Coliform 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: January 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: January 1, 2023 – March 31, 2023Rule: Stage 1 DBPREnforcement: 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: January 1, 2023 – December 31, 2023Rule: Stage 2 DBPREnforcement: Resolving — corrective action underway

TIER 3Resolved

Failed to conduct Level 1 Assessment

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

When: December 1, 2022 – June 3, 2023Rule: Consumer Confidence RuleEnforcement: Formal — state order issued

TIER 3Resolved

Monitoring Violation

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

When: October 1, 2022 – October 31, 2022Rule: Total Coliform RuleEnforcement: 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: August 1, 2022 – October 7, 2022Rule: 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, 2022 – September 30, 2022Enforcement: Formal — state order issued

TIER 3Resolved

Surface water treatment technique failure

When: July 1, 2022 – December 13, 2022Enforcement: Resolving — corrective action underway

TIER 3Resolved

Failed to conduct Level 1 Assessment

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

When: May 1, 2022 – June 28, 2022Rule: Consumer Confidence 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: April 1, 2022 – June 30, 2022Rule: Stage 1 DBPREnforcement: Formal — state order issued

TIER 3Resolved

Failed to conduct Level 1 Assessment

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

When: December 1, 2021 – June 28, 2022Rule: Consumer Confidence RuleEnforcement: Formal — state order issued

TIER 3Resolved

Failed to conduct Level 1 Assessment

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

When: November 1, 2021 – June 28, 2022Rule: Consumer Confidence RuleEnforcement: Formal — state order issued

TIER 3Resolved

Failed to conduct Level 1 Assessment

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

When: October 1, 2021 – June 28, 2022Rule: Consumer Confidence RuleEnforcement: Formal — state order issued

TIER 3Resolved

Monitoring Violation

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

When: September 1, 2021 – September 30, 2021Rule: Total Coliform RuleEnforcement: Resolving — corrective action underway

TIER 3Resolved

Failed to conduct Level 1 Assessment

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

When: July 1, 2021 – September 10, 2021Rule: Consumer Confidence RuleEnforcement: Resolving — corrective action underway

TIER 3Resolved

Disinfection byproduct treatment technique failure

When: July 1, 2021 – July 1, 2022Rule: Ground Water RuleEnforcement: Formal — state order issued

TIER 1 — URGENTResolved

Maximum Contaminant Level Violation

When: July 1, 2021 – July 31, 2021Rule: Total Coliform 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

Water Utility Details

SCUA Bylas

Population Served

3,160

Water Source

Groundwater

System ID

090400110

SCUA Upper Seven Mile

Population Served

8,478

Water Source

Groundwater

System ID

090400114

Frequently Asked Questions About San Carlos Water

Is San Carlos tap water safe to drink?

San Carlos, Arizona tap water receives a grade of F (0/100), which is considered failing. 0 contaminant(s) exceed EPA maximum contaminant levels and 922 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.

What contaminants are in San Carlos's water?

Of the 31 contaminants tested in San Carlos's water supply, the most notable include Lead (90th percentile). No contaminants exceed EPA legal limits. 1 contaminant(s) exceed EPA health goals (MCLGs), which are non-enforceable targets set at levels with no known health risk.

Does San Carlos have any water quality violations?

Yes, San Carlos has 922 EPA violation(s) on record, with the most recent in 2025. Violation types include MR, TT, RPT. 118 of these are health-based violations, which are the most serious category.

Do I need a water filter in San Carlos?

San Carlos water meets EPA standards, so a filter is not strictly necessary. However, some residents prefer the added security of a water filter. EPA health goals (MCLGs) are stricter than legal limits and are set at levels with zero expected health risk. 1 contaminant(s) exceed these stricter goals.

Where does San Carlos's tap water come from?

San Carlos's drinking water is sourced from groundwater and supplied by SCUA Bylas and 1 other water system(s). The system serves approximately 11,638 people. Groundwater is pumped from underground aquifers, which often provides natural filtration.

How often is San Carlos's water tested?

Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. San Carlos's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.

How does San Carlos's water compare to other cities in Arizona?

San Carlos's water quality score of 0/100 earns a grade of F, which is considered failing. This is a concerning score that suggests significant water quality issues. Visit our Arizona state page to see how all cities in the state compare.

What should I do if I'm concerned about San Carlos's water quality?

If you have concerns about San Carlos's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (SCUA Bylas) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.

Nearby Cities in Arizona

PhoenixD TucsonF MesaF El MirageF ScottsdaleC