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San Ysidro, NM Tap Water Quality 2026

Water quality report for San Ysidro, NM — PFAS, lead and copper results, violation history and state inspection findings from EPA SDWIS.

A look at San Ysidro's drinking water using EPA enforcement records: violations, lead and copper results, PFAS sampling and state inspection findings.

Main Utility: Dona Ana Mdwca PWSID: NM3554307 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead is 1.90 ppb, 13% of the action level and no violations are open. PFAS was detected below the federal limit.

C

San Ysidro earns a C for water quality

Graded on violations, lead, and PFAS, with state inspection findings.

Lead: 1.90 ppb — 13% of the federal action level
PFAS detected below the federal limit
34 violations since 2015, 14 health-based
No violations currently open
San Ysidro's lead level vs. all New Mexico community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: 1.90 ppb — 13% of the federal action level
✓ Lower lead than 53% of New Mexico utilities
Population Served
2107
~6584 connections
Water Source
Groundwater
Drawn from wells — SDWIS source code GW
Active Violations
0
34 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
13% of EPA action level
1.90 ppb
Action level: 15 ppb
The 90th-percentile lead result is 1.90 ppb, 13% of the 15 ppb federal action level. The action level is a treatment trigger, not a legal maximum, and it is measured across sampled taps rather than at any single home.

Contaminant Violations (2015–Present)

ContaminantTypeMeasuredLimitPeriodStatus
Public Notice OTHER — — 2024 Resolved
Groundwater Rule TREATMENT TECHNIQUE — — 2024 Resolved
Groundwater Rule TREATMENT TECHNIQUE — — 2024 Resolved
Groundwater Rule TREATMENT TECHNIQUE — — 2024 Resolved
Groundwater Rule TREATMENT TECHNIQUE — — 2024 Resolved
Groundwater Rule TREATMENT TECHNIQUE — — 2024 Resolved
Groundwater Rule TREATMENT TECHNIQUE — — 2024 Resolved
Groundwater Rule TREATMENT TECHNIQUE — — 2024 Resolved
Groundwater Rule TREATMENT TECHNIQUE — — 2024 Resolved
Groundwater Rule TREATMENT TECHNIQUE — — 2024 Resolved
Groundwater Rule TREATMENT TECHNIQUE — — 2024 Resolved
Public Notice OTHER — — 2024 Resolved
Public Notice OTHER — — 2024 Resolved
Chlorine MONITORING AND REPORTING — 4.0 mg/L 2024 Resolved
Chlorine MONITORING AND REPORTING — 4.0 mg/L 2023 Resolved
Revised Total Coliform Rule MONITORING FAILURE — — 2023 Resolved
Revised Total Coliform Rule MONITORING FAILURE — — 2023 Resolved
Chlorine MONITORING AND REPORTING — 4.0 mg/L 2023 Resolved
Public Notice OTHER — — 2022 Resolved
Consumer Confidence Rule OTHER — — 2021 Resolved
Chlorine MONITORING AND REPORTING — 4.0 mg/L 2021 Resolved
Groundwater Rule TREATMENT TECHNIQUE — — 2020 Resolved
Groundwater Rule TREATMENT TECHNIQUE — — 2020 Resolved
Asbestos MONITORING AND REPORTING — 7 MFL 2020–2022 Resolved
Lead and Copper Rule MONITORING AND REPORTING — TT 2018 Resolved
Consumer Confidence Rule OTHER — — 2018 Resolved
TTHM MONITORING AND REPORTING — 0.080 mg/L 2018 Resolved
Total Haloacetic Acids (HAA5) MONITORING AND REPORTING — 0.060 mg/L 2018 Resolved
Public Notice OTHER — — 2018 Resolved
Public Notice OTHER — — 2017 Resolved
Public Notice OTHER — — 2017 Resolved
Groundwater Rule TREATMENT TECHNIQUE — — 2016 Resolved
Groundwater Rule TREATMENT TECHNIQUE — — 2016 Resolved
Public Notice OTHER — — 2015 Resolved
Understanding violation types MCL violations mean a contaminant exceeded the federal maximum limit — the most serious type.
TT (Treatment Technique) violations mean required treatment procedures weren't followed, but don't necessarily mean contamination occurred.

Violation History

34 violations are on record since 2015, of which 14 were health-based. All have been resolved and none remain open.

About the Main Water System

Utility Dona Ana Mdwca
PWSID NM3554307
Water source Groundwater — Drawn from wells — SDWIS source code GW
Population served 2,107
Service connections 6,584
Systems serving this area 2
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is San Ysidro tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open. Lead is 1.90 ppb, 13% of the action level.
Does San Ysidro water have PFAS? ▼
PFAS was detected but stayed below the federal limit.
Who supplies water to San Ysidro? ▼
Dona Ana Mdwca (PWSID NM3554307), one of 2 systems serving this area. Groundwater. Drawn from wells — SDWIS source code GW
When was this system last inspected? ▼
It was last inspected on 2023-12-13. Inspectors recorded 2 significant deficiencies.

What Should San Ysidro Residents Do?

1
Read your annual water report
Your supplier publishes a Consumer Confidence Report each July covering the prior year.
2
Check for a lead service line
Lead reaches tap water mainly through service lines and household plumbing. Suppliers now publish an inventory identifying lead lines.
3
Flush before drinking
If water has sat in pipes more than six hours, run the cold tap for two minutes before drinking or cooking.

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