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Community Water System · PWS NM3505929

Costilla Mdwca

Costilla, New Mexico 87524 - drinking water served from groundwater sources to 244 people, tracked in EPA SDWIS and UCMR5.

244
People served
244
EPA violations
64
Health-based
Untested
UCMR5 result

The verdict

EPA records 244 drinking-water violations at Costilla Mdwca, 26% of them health-based - above the New Mexico per-system average.

244
Total EPA violations on record
26%
Health-based (MCL / treatment failure)
244
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Costilla Mdwca

Costilla Mdwca is a local-owned community water system that delivers drinking water to 244 residents in Costilla, New Mexico (Taos County) through 100 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 244 total violations for this system , of which 64 (26%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 109 monitoring and reporting violations are on file. The most recent violation on record dates to 2025.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 54 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 New Mexico, EPA tracks 1,037 public water systems serving 2,027,497 people, with 154,522 cumulative violations and 38,650 health-based violations on record. About 97% of systems in the state carry at least one violation, and state-wide the average per system is 149 violations. Statewide, 70 of 72 UCMR5-tested systems have reported PFAS detections (97.2%).

Costilla Mdwca's 244 violations sit above the New Mexico 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
244
Total Violations
244
Health-Based Violations
64
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Local
Connections
100
County
Taos
School/Daycare
No
MCL Violations
34
Monitoring Violations
109
Treatment Tech Violations
30

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MR 54 2014
Coliform (TCR) MCL 34 2014
Consumer Confidence Rule Other 30 2025
Groundwater Rule TT 28 2016
Revised Total Coliform Rule MON 18 2020
Public Notice Other 14 2021
Chlorine MR 11 2021
Lead and Copper Rule MR 8 2019
TTHM MR 7 2018
Total Haloacetic Acids (HAA5) MR 7 2018
Coliform (Pre-TCR) Other 6 1990
E. COLI MR 4 2012
LEAD AND COPPER RULE REVISIONS TT 2 2024
LEAD AND COPPER RULE REVISIONS RPT 2 2024
Groundwater Rule Other 2 2024

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 Costilla Mdwca.

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 NM3505929 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

New Mexico Drinking Water Authority

New Mexico's primacy agency administers the Safe Drinking Water Act locally. Search EPA SDWIS for the current state contact, or use the state's public health or environment department portal.

Find NM regulator via EPA SDWIS

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
2025 Consumer Confidence Rule Other 30 SDWIS / NM3505929 / 7000
2024 LEAD AND COPPER RULE REVISIONS TT 2 SDWIS / NM3505929 / 5200
2024 LEAD AND COPPER RULE REVISIONS RPT 2 SDWIS / NM3505929 / 5200
2024 Groundwater Rule Other 2 SDWIS / NM3505929 / 0700
2021 Public Notice Other 14 SDWIS / NM3505929 / 7500
2021 Chlorine MR 11 SDWIS / NM3505929 / 0999
2020 Revised Total Coliform Rule MON 18 SDWIS / NM3505929 / 8000
2019 Lead and Copper Rule MR 8 SDWIS / NM3505929 / 5000
2018 TTHM MR 7 SDWIS / NM3505929 / 2950
2018 Total Haloacetic Acids (HAA5) MR 7 SDWIS / NM3505929 / 2456
2016 Groundwater Rule TT 28 SDWIS / NM3505929 / 0700
2014 Coliform (TCR) MR 54 SDWIS / NM3505929 / 3100
2014 Coliform (TCR) MCL 34 SDWIS / NM3505929 / 3100
2012 E. COLI MR 4 SDWIS / NM3505929 / 3014
1990 Coliform (Pre-TCR) Other 6 SDWIS / NM3505929 / 3000

How Costilla Mdwca Compares

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

Metric Costilla Mdwca New Mexico avg Federal benchmark
Total violations 244 149 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 64 37.3 Indicates a contaminant exceeded a federal MCL
PFAS detection None 97.2% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 244 1,955 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 1,037 regulated public water systems in New Mexico.

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 Costilla Mdwca water safe to drink? ▼
Costilla Mdwca (PWS ID: NM3505929) has 244 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 244 people using Groundwater sources.
How many people does Costilla Mdwca serve? ▼
Costilla Mdwca serves 244 people in Costilla, New Mexico. It is a Local-owned system using Groundwater water sources with 100 service connections.
What type of violations does Costilla Mdwca have? ▼
Costilla Mdwca has 244 total violations: 64 health-based violations (MCL exceedances or treatment failures), 109 monitoring/reporting violations, and 30 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Costilla Mdwca water? ▼
No PFAS testing data is available for Costilla Mdwca under the EPA's UCMR5 monitoring program.
What water source does Costilla Mdwca use? ▼
Costilla Mdwca uses Groundwater as its primary water source. It is classified as a Community Water System (CWS), serving residential populations year-round.
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.