Public water system record
San Ysidro Water Supply System
Serves San Ysidro, Sandoval County, NM · 166 people served
Federal records show 30 health-based violations and 32 monitoring/reporting issues for San Ysidro Water Supply System in the last ten years, including an unresolved Groundwater Rule violation.
System profile
- Health-based violations, last 10 years
- 30
- Resolved
- 22
- Unresolved
- 3
- Archived by EPA
- 5
- Any acute record
- No
- Monitoring issues, last 10 years
- 32
Key facts
- San Ysidro Water Supply System draws water from 1 well and 2 infiltration galleries.
- Highest measured level in the last 10 years: Arsenic, 0.11 mg/L, federal limit 0.01 mg/L (11 times the limit), 2022.
- Most recent formal enforcement: compliance order (no penalty) by New Mexico, September 2022.
- Record on file since 1984, with 22 health-based violations before October 19, 2016.
Check whether San Ysidro Water Supply System serves your address
Health-based violations
Since October 2016Violation data reflects EPA records through March 2026. For the most current status, visit the EPA ECHO database.
| Contaminant | Rule family | Start date | Status | Acute |
|---|---|---|---|---|
|
Groundwater Rule
Treatment technique failure
|
140 | Jul 12, 2025 | Active | No |
|
Groundwater Rule
Treatment technique failure
|
140 | Jul 12, 2025 | Active | No |
|
LEAD AND COPPER RULE REVISIONS
Treatment technique failure
|
350 | Oct 17, 2024 | Active | No |
|
Fluoride
Contaminant limit exceeded
Measured 5 mg/L, federal limit 4 mg/L (1.3 times the limit)
|
330 | Jul 1, 2024 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 5.2 mg/L, federal limit 4 mg/L (1.3 times the limit)
|
330 | Apr 1, 2024 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 5 mg/L, federal limit 4 mg/L (1.3 times the limit)
|
330 | Jan 1, 2024 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 4.8 mg/L, federal limit 4 mg/L (1.2 times the limit)
|
330 | Oct 1, 2023 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 4.5 mg/L, federal limit 4 mg/L (1.1 times the limit)
|
330 | Jul 1, 2023 | Resolved | No |
|
Arsenic
Contaminant limit exceeded
Measured 0.038 mg/L, federal limit 0.01 mg/L (3.8 times the limit)
|
330 | Apr 1, 2023 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 4.6 mg/L, federal limit 4 mg/L (1.2 times the limit)
|
330 | Apr 1, 2023 | Resolved | No |
|
Arsenic
Contaminant limit exceeded
Measured 0.056 mg/L, federal limit 0.01 mg/L (5.6 times the limit)
|
330 | Jan 1, 2023 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 4.8 mg/L, federal limit 4 mg/L (1.2 times the limit)
|
330 | Jan 1, 2023 | Resolved | No |
|
Arsenic
Contaminant limit exceeded
Measured 0.11 mg/L, federal limit 0.01 mg/L (11 times the limit)
|
330 | Oct 1, 2022 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 5.1 mg/L, federal limit 4 mg/L (1.3 times the limit)
|
330 | Oct 1, 2022 | Resolved | No |
|
Arsenic
Contaminant limit exceeded
Measured 0.11 mg/L, federal limit 0.01 mg/L (11 times the limit)
|
330 | Jul 1, 2022 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 5.6 mg/L, federal limit 4 mg/L (1.4 times the limit)
|
330 | Jul 1, 2022 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 5.5 mg/L, federal limit 4 mg/L (1.4 times the limit)
|
330 | Apr 1, 2022 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 6.7 mg/L, federal limit 4 mg/L (1.7 times the limit)
|
330 | Jan 1, 2022 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 6.1 mg/L, federal limit 4 mg/L (1.5 times the limit)
|
330 | Oct 1, 2021 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 5.7 mg/L, federal limit 4 mg/L (1.4 times the limit)
|
330 | Jul 1, 2021 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 5.6 mg/L, federal limit 4 mg/L (1.4 times the limit)
|
330 | Apr 1, 2021 |
Archived
Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.
|
No |
|
Fluoride
Contaminant limit exceeded
Measured 5.3 mg/L, federal limit 4 mg/L (1.3 times the limit)
|
330 | Jan 1, 2021 |
Archived
Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.
|
No |
|
Fluoride
Contaminant limit exceeded
Measured 5.3 mg/L, federal limit 4 mg/L (1.3 times the limit)
|
330 | Oct 1, 2020 |
Archived
Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.
|
No |
|
Fluoride
Contaminant limit exceeded
Measured 5.7 mg/L, federal limit 4 mg/L (1.4 times the limit)
|
330 | Jul 1, 2020 |
Archived
Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.
|
No |
|
Fluoride
Contaminant limit exceeded
Measured 4.5 mg/L, federal limit 4 mg/L (1.1 times the limit)
|
330 | Apr 1, 2020 |
Archived
Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.
|
No |
|
Groundwater Rule
Treatment technique failure
|
140 | Jul 8, 2017 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 4.1 mg/L, federal limit 4 mg/L (at or just above the limit)
|
330 | Apr 1, 2017 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 5.3 mg/L, federal limit 4 mg/L (1.3 times the limit)
|
330 | Jan 1, 2017 | Resolved | No |
|
Fluoride
Contaminant limit exceeded
Measured 5.2 mg/L, federal limit 4 mg/L (1.3 times the limit)
|
330 | Oct 1, 2016 | Resolved | No |
|
Stage 1 Disinfection Byproducts Rule
Treatment technique failure
|
210 | Aug 31, 2012 | Resolved | No |
Monitoring and reporting issues
Since October 2016Missed tests or reports, not contaminants found above a limit.
| Issue | Start date | Status |
|---|---|---|
|
LEAD AND COPPER RULE REVISIONS
RPT
|
Oct 17, 2024 | Active |
|
Haloacetic Acids (HAA5)
Monitoring and reporting
|
Nov 1, 2023 | Resolved |
|
Total Trihalomethanes (TTHMs)
Monitoring and reporting
|
Nov 1, 2023 | Resolved |
|
Haloacetic Acids (HAA5)
Monitoring and reporting
|
Oct 1, 2023 | Resolved |
|
Total Trihalomethanes (TTHMs)
Monitoring and reporting
|
Oct 1, 2023 | Resolved |
|
Arsenic
Monitoring and reporting
|
Oct 1, 2022 | Resolved |
|
Public Notice
OTHER
|
May 8, 2022 | Resolved |
|
Arsenic
Monitoring and reporting
|
Apr 1, 2022 | Resolved |
|
Arsenic
Monitoring and reporting
|
Jan 1, 2022 | Resolved |
|
Fluoride
Monitoring and reporting
|
Jan 1, 2022 | Resolved |
|
Fluoride
Monitoring and reporting
|
Oct 1, 2021 | Resolved |
|
Arsenic
Monitoring and reporting
|
Oct 1, 2021 | Resolved |
|
Consumer Confidence Rule
OTHER
|
Oct 1, 2021 | Resolved |
|
Arsenic
Monitoring and reporting
|
Jul 1, 2021 | Resolved |
|
Fluoride
Monitoring and reporting
|
Jul 1, 2021 | Resolved |
|
Arsenic
Monitoring and reporting
|
Apr 1, 2021 | Resolved |
|
Arsenic
Monitoring and reporting
|
Jan 1, 2021 | Resolved |
|
Public Notice
OTHER
|
Oct 3, 2020 | Resolved |
|
Haloacetic Acids (HAA5)
Monitoring and reporting
|
Oct 1, 2020 | Resolved |
|
Arsenic
Monitoring and reporting
|
Oct 1, 2020 | Resolved |
|
Revised Total Coliform Rule
Monitoring violation
|
Sep 1, 2020 | Resolved |
|
Revised Total Coliform Rule
Monitoring violation
|
Aug 1, 2020 | Resolved |
|
Chlorine
Monitoring and reporting
|
Jul 1, 2020 | Resolved |
|
Arsenic
Monitoring and reporting
|
Jul 1, 2020 | Resolved |
|
Consumer Confidence Rule
OTHER
|
Jul 1, 2020 | Resolved |
|
Public Notice
OTHER
|
Jun 5, 2020 | Resolved |
|
Arsenic
Monitoring and reporting
|
Apr 1, 2020 | Resolved |
|
Arsenic
Monitoring and reporting
|
Jan 1, 2020 | Resolved |
|
Total Trihalomethanes (TTHMs)
Monitoring and reporting
|
Jan 1, 2020 | Resolved |
|
Public Notice
OTHER
|
Apr 20, 2017 | Resolved |
|
Lead and Copper Rule
Monitoring and reporting
|
Oct 1, 2015 | Resolved |
|
Public Notice
OTHER
|
Jul 31, 2015 | Resolved |
Full record since 1984
EPA's records for San Ysidro Water Supply System go back to 1984. Before October 19, 2016 they list 22 health-based violations (17 resolved, 5 archived by EPA without a recorded fix) and 35 monitoring or reporting violations.
| Violations that began in | Health-based | Monitoring and reporting |
|---|---|---|
| 1980s | 3 | 0 |
| 1990s | 3 | 7 |
| 2000s | 0 | 22 |
| 2010 to October 18, 2016 | 16 | 6 |
| October 19, 2016 to 2019 | 3 | 1 |
| 2020s | 25 | 29 |
Most recent health-based violation before October 19, 2016: Fluoride, began October 2016, Resolved.
Show all 22 health-based violations before October 19, 2016
| Contaminant | Start date | Status |
|---|---|---|
|
Fluoride
Contaminant limit exceeded
Measured 5.2 mg/L, federal limit 4 mg/L (1.3 times the limit)
|
Oct 1, 2016 | Resolved |
|
Fluoride
Contaminant limit exceeded
Measured 5.2 mg/L, federal limit 4 mg/L (1.3 times the limit)
|
Jul 1, 2016 | Resolved |
|
Fluoride
Contaminant limit exceeded
Measured 5.2 mg/L, federal limit 4 mg/L (1.3 times the limit)
|
Apr 1, 2016 | Resolved |
|
Fluoride
Contaminant limit exceeded
Measured 5.3 mg/L, federal limit 4 mg/L (1.3 times the limit)
|
Jan 1, 2016 | Resolved |
|
Fluoride
Contaminant limit exceeded
Measured 5.5 mg/L, federal limit 4 mg/L (1.4 times the limit)
|
Oct 1, 2015 | Resolved |
|
Fluoride
Contaminant limit exceeded
Measured 5.8 mg/L, federal limit 4 mg/L (1.5 times the limit)
|
Jul 1, 2015 | Resolved |
|
Fluoride
Contaminant limit exceeded
Measured 5.8 mg/L, federal limit 4 mg/L (1.5 times the limit)
|
Apr 1, 2015 | Resolved |
|
Fluoride
Contaminant limit exceeded
Measured 5.9 mg/L, federal limit 4 mg/L (1.5 times the limit)
|
Jan 1, 2015 | Resolved |
|
Fluoride
Contaminant limit exceeded
Measured 5.8 mg/L, federal limit 4 mg/L (1.5 times the limit)
|
Oct 1, 2014 | Resolved |
|
Fluoride
Contaminant limit exceeded
Measured 5.6 mg/L, federal limit 4 mg/L (1.4 times the limit)
|
Jul 1, 2014 | Resolved |
|
Fluoride
Contaminant limit exceeded
Measured 4.3 mg/L, federal limit 4 mg/L (1.1 times the limit)
|
Apr 1, 2014 | Resolved |
|
Stage 1 Disinfection Byproducts Rule
Treatment technique failure
|
Aug 31, 2012 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.13 mg/L, federal limit 0.08 mg/L (1.6 times the limit)
|
Jan 1, 2011 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.115 mg/L, federal limit 0.08 mg/L (1.4 times the limit)
|
Oct 1, 2010 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.125 mg/L, federal limit 0.08 mg/L (1.6 times the limit)
|
Jul 1, 2010 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.082 mg/L, federal limit 0.08 mg/L (at or just above the limit)
|
Apr 1, 2010 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Aug 1, 1999 | Resolved |
|
Arsenic
Contaminant limit exceeded
|
Jan 1, 1996 | Archived |
|
Fluoride
Contaminant limit exceeded
|
Jan 1, 1996 | Archived |
|
Arsenic
Contaminant limit exceeded
|
Jan 1, 1986 | Archived |
|
Fluoride
Contaminant limit exceeded
|
Jul 1, 1984 | Archived |
|
Arsenic
Contaminant limit exceeded
|
Jul 1, 1984 | Archived |
Enforcement actions
New Mexico regulators and EPA took 3 formal enforcement actions against San Ysidro Water Supply System between 1999 and 2022. The most recent was a compliance order (no penalty) in September 2022.
| Date | By | Action | Violations covered |
|---|---|---|---|
| Sep 16, 2022 | New Mexico | Compliance order (no penalty) | 17 violations (17 health-based): Fluoride |
| Sep 22, 2000 | EPA | Compliance order (no penalty) | 2 violations: Consumer Confidence Rule |
| Mar 31, 1999 | EPA | Compliance order (no penalty) | 3 violations (2 health-based): Fluoride, Arsenic, Total Coliform |
What the violations mean
Fluoride
21 incidentsFluoride exceeded the federal limit
Excessive fluoride can cause dental and skeletal fluorosis
Arsenic
4 incidentsArsenic exceeded the federal limit
Long-term arsenic exposure is linked to cancer and cardiovascular effects
Groundwater Rule
3 incidentsThe system did not complete a treatment step or action that the Groundwater Rule requires (a treatment technique violation).
The utility had to notify customers about each of these violations.
LEAD AND COPPER RULE REVISIONS
1 incidentThe system did not complete a treatment step or action that the LEAD AND COPPER RULE REVISIONS requires (a treatment technique violation).
The utility had to notify customers about this violation.
Stage 1 Disinfection Byproducts Rule
1 incidentThe system did not meet a treatment requirement of the Stage 1 Disinfectants and Disinfection Byproducts Rule
Byproducts form when disinfectants react with natural material in water. Long-term exposure above federal limits may increase cancer risk
Where the water comes from
San Ysidro Water Supply System draws water from 1 well and 2 infiltration galleries.
Annual water quality report
San Ysidro Water Supply System must give its customers an annual water quality report (Consumer Confidence Report) by July 1, with the levels its tests found in the previous year.
Systems serving 500 or fewer people may meet the rule by telling customers the report is available on request, so you may need to ask San Ysidro Water Supply System for a copy.
Find a posted report with EPA's Consumer Confidence Report search
Testing your own water
To test the water at your tap, or a private well this record does not cover, use a laboratory certified for drinking water by New Mexico.
Certified drinking water labs by state EPA guidance for private wells