Public water system · NM3505929
ActiveCostilla Mdwca
At a glance
Costilla Mdwca (PWSID NM3505929) is an active community water system in Taos County, New Mexico. It reports serving 244 people through 100 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in March 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
244
Service connections
100
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Costilla Mdwca compare with other water systems in Taos County?
By EPA's size categories, Costilla Mdwca is a very small system (500 people or fewer). Taos County has 94 active public water systems. Its population served is roughly in line with the county average of 266 people per system, and accounts for 1% of the 25,046 people reported by systems filed under the county. Across New Mexico, the 1,165 active systems average 1,885 people each. Nationally, the average active community water system reports serving 6,703 people, so Costilla Mdwca is well below that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. New Mexico has 645 active community water systems, 55% of the state's 1,165 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 1,009 New Mexico systems (87%) list groundwater as their primary source.
Who owns and regulates Costilla Mdwca?
EPA lists Costilla Mdwca as owned by a local government. The NM state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 36 of the 94 active systems in Taos County (38%) are also owned by a local government.
Does Costilla Mdwca have drinking water violations?
Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in March 2026. The violations listed here began between July 2023 and March 2026. By type: 5 public notice, recordkeeping or other, 5 required treatment not met, 1 monitoring and 1 reporting. The contaminant or rule involved most often is Groundwater Rule (5 of them). EPA lists 6 as unaddressed, 3 as resolved, 2 as addressed and 1 as archived. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed. Addressed means the violation is not resolved or archived and is covered by formal enforcement. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2026-03-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Archived |
| 2025-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2025-03-07 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Unaddressed |
| 2024-10-17 | ReportingLSL Reporting · code 4G | Lead and Copper Rule Revisionscode 5200 | No | Addressed |
| 2024-10-17 | Required treatment not metLSL Inventory · code 2E | Lead and Copper Rule Revisionscode 5200 | Yes | Addressed |
| 2024-07-03 | Required treatment not metFailure To Address Deficiency · code 45 | Groundwater Rulecode 0700 | Yes | Unaddressed |
| 2024-07-03 | Required treatment not metFailure To Address Deficiency · code 45 | Groundwater Rulecode 0700 | Yes | Unaddressed |
| 2024-07-03 | Required treatment not metFailure To Address Deficiency · code 45 | Groundwater Rulecode 0700 | Yes | Unaddressed |
| 2024-07-03 | Required treatment not metFailure To Address Deficiency · code 45 | Groundwater Rulecode 0700 | Yes | Unaddressed |
| 2024-04-07 | Public notice, recordkeeping or otherFailure to Consult with State · code 20 | Groundwater Rulecode 0700 | No | Unaddressed |
| 2023-10-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2023-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Costilla Mdwca: frequently asked questions
Who runs Costilla Mdwca?
Costilla Mdwca (PWSID NM3505929) is a community water system owned by a local government. It is regulated by the NM state drinking water program.
How many people does Costilla Mdwca serve?
Costilla Mdwca reports serving 244 people through 100 service connections in Taos County, New Mexico.
Where does Costilla Mdwca get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Costilla Mdwca have any drinking water violations?
Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in March 2026. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Costilla Mdwca's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in March 2026. For current results, consult the system's annual water quality report, EPA ECHO, or the NM state drinking water program.
Where can I find Costilla Mdwca's water quality report?
As a community water system, Costilla Mdwca must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Taos County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Taos Municipal Water System | Taos | 5,528 | Community | Groundwater |
| Questa Water System | Taos | 2,337 | Community | Groundwater |
| El Prado Water & Sanitation District | Taos | 1,076 | Community | Groundwater |
| Village of Taos Ski Valley | Taos | 1,025 | Community | Groundwater |
| Llano Quemado Mdwca | Taos | 800 | Community | Groundwater |
| Ranchos De Taos Mdwca | Taos | 750 | Community | Groundwater |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Costilla Mdwca, PWSID NM3505929, New Mexico”, https://aquacensus.com/water-systems/new-mexico/costilla-mdwca-nm3505929 (data as of October 1, 2026).