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County water report

Los Alamos County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Los Alamos County, New Mexico.

Water grade

A

Water score

86.0

State rank

#2

of 32

Health violations

0

EPA SDWIS, 5-year lookback

Watershed impaired

35.7%

115 water bodies assessed

Monitoring sites

N/A

EPA Water Quality Portal

Live streamflow

No gauge

Primary USGS station not mapped

Water at a glance

Key Water Indicators for Los Alamos County

EPA SDWIS

Safety Grade

A

Score: 86.0 / 100

EPA SDWIS

Active Violations

0

5-year health-based lookback

EPA ATTAINS

Watershed Health

36% impaired

115 bodies assessed

USGS NWIS

Streamflow Snapshot

No gauge

Primary USGS gauge not mapped

EPA WQP

Monitoring Sites

N/A

Rolling 5-year window

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

A

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

86.0/100

Health violations

0

Health-based violations

Violations per 100K served

0.0

Population-normalized SDWIS rate

Editorial analysis

Understanding Los Alamos County’s Water

Drinking Water Quality Overview

EPA SDWIS

Los Alamos County earns an A grade for drinking water quality, scoring 86.0 out of 100. EPA's Safe Drinking Water Information System (SDWIS) records zero health-based violations over the past five years — a strong compliance signal for a large county.

Watershed Conditions

EPA ATTAINS

Under the Clean Water Act §303(d), EPA ATTAINS tracks whether waterways meet quality standards for drinking, recreation, and aquatic life (reporting cycle: 2022). A substantial 35.7% of assessed waterways are impaired (41 of 115 water bodies) across Los Alamos County's watersheds. The leading impairment causes are polychlorinated biphenyls (pcbs) and alpha particles. Impairment does not mean tap water is unsafe — it measures ambient waterway conditions upstream of treatment, not finished drinking water.

Editorial advisory

What the data suggests for Los Alamos County

Water Verdict

Los Alamos County, New Mexico receives an excellent water quality assessment with a grade of A and a score of 86.0 out of 100. The water supply meets or exceeds federal safety standards, and residents can generally drink tap water with confidence. Separately, EPA ATTAINS assessments cover 115 water bodies in the county's watershed, with 35.7% listed as impaired under the Clean Water Act — a source-water measure that is tracked independently of tap-water compliance.

Violation Context

EPA SDWIS records for Los Alamos County, New Mexico show zero health-based violations, indicating that the county's water systems met all federal safety standards during the reporting period. The violation rate is zero per 100,000 people served, which is the best possible outcome. The most recent Clean Water Act assessment cycle on file for the county's watershed is 2022.

Consumer Guidance

The EPA compliance record for Los Alamos County shows no recent health-based violations. No health-based violations have been recorded, placing Los Alamos County in the top tier for drinking-water safety. Los Alamos County's drinking-water compliance score is 86.0 out of 100. As a routine precaution, requesting your utility's annual Consumer Confidence Report each July gives you a full list of detected contaminants and their treatment levels.

Regional Context

Los Alamos County has better water quality than the average county in New Mexico. Its water score is 64.3 points higher than the state average, indicating stronger water system performance relative to neighboring counties.

Advisory text summarizes county-level public records and is not a replacement for your utility's current Consumer Confidence Report or direct local notices.

Contaminants & Resources

Key issues flagged in Los Alamos County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Polychlorinated Biphenyls (Pcbs)

    Impairment cause per EPA Clean Water Act §303(d) assessment

  • 2

    Alpha Particles

    Impairment cause per EPA Clean Water Act §303(d) assessment

  • 3

    Aluminum, Total

    Impairment cause per EPA Clean Water Act §303(d) assessment

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Los Alamos County

EPA How's My Waterway

Interactive watershed health data for Los Alamos County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Los Alamos County

Consumer Confidence Reports (NM)

Annual water quality reports from utilities in New Mexico

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

35.7%

41 of 115 assessed

Moderate concern

Top Impairment Causes

  • 1

    POLYCHLORINATED BIPHENYLS (PCBS)

  • 2

    ALPHA PARTICLES

  • 3

    ALUMINUM, TOTAL

Source: EPA ATTAINS · Reporting cycle 2022

Impairment is determined under the Clean Water Act §303(d): a water body is impaired when it fails to meet state-defined quality standards for designated uses (drinking, recreation, aquatic life). Assessment coverage varies by state; counties without assessed water bodies are not shown.

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Safety Grade for Los Alamos County:C — Moderate

Some violations or watershed impairment detected.

Estimates use the national average residential water rate ($0.0068/gal, EPA/AWWA 2023) and EPA WaterSense per-person consumption baseline (75 gal/person/day). Actual bills vary by utility, usage tier, and local infrastructure fees. For informational purposes only.

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Los Alamos County has good water quality

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Frequently Asked Questions

What is the water quality in Los Alamos County, New Mexico?
Los Alamos County, New Mexico has a drinking-water quality grade of A with a score of 86.0/100, based on EPA SDWIS compliance data. The county has 0 health-based drinking water violations over the past 5 years. Watershed health, monitoring records, and streamflow snapshots are reported separately on this page.
Are there any water violations in Los Alamos County?
Los Alamos County has 0 health-based drinking water violations recorded by the EPA over the past 5 years. Health-based violations indicate instances where contaminant levels exceeded EPA Maximum Contaminant Levels (MCLs). Zero violations is an excellent record indicating consistent compliance with federal drinking water standards.
How healthy are the watersheds in Los Alamos County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 35.7% of Los Alamos County's 115 assessed water bodies are classified as impaired (41 impaired). The top reported causes are POLYCHLORINATED BIPHENYLS (PCBS), ALPHA PARTICLES, ALUMINUM, TOTAL. Impairment means the water body fails to meet state quality standards for at least one designated use — drinking water source, recreation, aquatic life, or fish consumption. Note: watershed impairment doesn't always translate to tap-water issues; treatment plants can remove most regulated contaminants.
How does Los Alamos County water compare to the New Mexico average?
Los Alamos County's SDWIS water quality score of 86.0/100 is higher than the New Mexico state average of 21.7. The average water quality grade across New Mexico is F, based on data from 32 counties with available SDWIS data.
Is tap water safe to drink in Los Alamos County?
Based on EPA SDWIS data, Los Alamos County has a water quality grade of A (86.0/100). This indicates good to excellent water quality with strong SDWIS compliance. The grade speaks to the public water system, not the watershed — for watershed-level concerns, see the Watershed Health zone. For the most up-to-date information, contact your local water utility or review your Consumer Confidence Report (CCR).
Does Los Alamos County have clean drinking water?
Los Alamos County has 0 health-based drinking water violations according to EPA records. With a water quality score of 86.0/100 and grade A, the county's drinking water meets EPA standards with no recorded health violations. Note: drinking-water compliance speaks to the public water system, not necessarily to the watershed itself — check the Watershed Health zone for ATTAINS §303(d) data.
How does Los Alamos County rank for water quality in New Mexico?
Los Alamos County ranks #2 out of 32 counties in New Mexico by SDWIS water quality score (1 = best). With a score of 86.0/100, it falls in the top third of counties statewide. The ranking reflects EPA SDWIS compliance only — not watershed impairment, monitoring density, or streamflow, which are tracked separately on this page.

Counties with Similar Water Quality

De Baca County

New Mexico

A

86.0

Water score

Chaves County

New Mexico

C

58.1

Water score

Bernalillo County

New Mexico

D

43.4

Water score

Data Sources

Drinking-water compliance data from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. Scores reflect compliance history and health-based violation counts.

Watershed health and impaired-waterway data from the EPA ATTAINS Clean Water Act §303(d) assessments, state-reported and EPA-finalized.

Disclaimer: This data is informational only. It is not health, legal, or professional advice. For concerns about your specific water supply, contact your local water utility.

By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

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