Public water system · NM3535021
ActiveAlcalde Mdwca
At a glance
Alcalde Mdwca (PWSID NM3535021) is an active community water system in Rio Arriba County, New Mexico. It reports serving 927 people through 309 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, 10 are health-based, and the most recent began in January 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
927
Service connections
309
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Alcalde Mdwca compare with other water systems in Rio Arriba County?
By EPA's size categories, Alcalde Mdwca is a small system (501 to 3,300 people). Rio Arriba County has 63 active public water systems, and Alcalde Mdwca is the 6th-largest of them by population served. Its population served is about twice the county average of 463 people per system, and accounts for 3.2% of the 29,192 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 Alcalde 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 Alcalde Mdwca?
EPA lists Alcalde 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. 41 of the 63 active systems in Rio Arriba County (65%) are also owned by a local government.
Does Alcalde Mdwca have drinking water violations?
Of the 12 most recent violations in EPA's records, 10 are health-based, and the most recent began in January 2026. The violations listed here began between October 2021 and January 2026. By type: 10 contaminant level above the legal limit, 1 public notice, recordkeeping or other and 1 monitoring and reporting. The contaminant or rule involved most often is Arsenic (10 of them). EPA lists 10 as resolved, 1 as archived and 1 as unaddressed. 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. 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. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2026-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Archived |
| 2025-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Resolved |
| 2025-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Resolved |
| 2025-03-21 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Unaddressed |
| 2025-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Resolved |
| 2024-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Resolved |
| 2024-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Resolved |
| 2024-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Resolved |
| 2024-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Resolved |
| 2023-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Resolved |
| 2023-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Resolved |
| 2021-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | 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.
Alcalde Mdwca: frequently asked questions
Who runs Alcalde Mdwca?
Alcalde Mdwca (PWSID NM3535021) is a community water system owned by a local government. It is regulated by the NM state drinking water program.
How many people does Alcalde Mdwca serve?
Alcalde Mdwca reports serving 927 people through 309 service connections in Rio Arriba County, New Mexico.
Where does Alcalde 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 Alcalde Mdwca have any drinking water violations?
Of the 12 most recent violations in EPA's records, 10 are health-based, and the most recent began in January 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 Alcalde 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, 10 are health-based, and the most recent began in January 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 Alcalde Mdwca's water quality report?
As a community water system, Alcalde 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 Rio Arriba County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Espanola Water System | Rio Arriba | 12,012 | Community | Groundwater |
| Chama Water System | Rio Arriba | 1,573 | Community | Surface water |
| Agua Sana Wua | Rio Arriba | 1,514 | Community | Groundwater |
| El Rito Regional Water & Waste Water Asn | Rio Arriba | 1,200 | Community | Groundwater |
| Greater Chimayo Mdwca | Rio Arriba | 1,050 | Community | Groundwater |
| Chamita Mdwca | Rio Arriba | 902 | Community | Groundwater |
Related pages
Working with water-system records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “Alcalde Mdwca, PWSID NM3535021, New Mexico”, https://aquacensus.com/water-systems/new-mexico/alcalde-mdwca-nm3535021 (data as of October 1, 2026).