Arsenic in Drinking Water in New Mexico
What residents of New Mexico need to know about arsenic in drinking water — including natural geological sources, private well risk, which utilities have documented violations, and how to remove arsenic from tap water.
Source: EPA SDWIS, New Mexico Environment Department, USGS · Last reviewed: 2025-01-01
Quick Answer
Is arsenic in drinking water a concern in New Mexico?
Yes — New Mexico has some of the most severe naturally occurring arsenic contamination in the United States. The state's volcanic, geothermal, and Basin and Range geology creates widespread elevated arsenic in groundwater across a large portion of the state. Multiple New Mexico public water systems have historically exceeded the MCL, and many small communities have required treatment or source switching to achieve compliance.
Where does arsenic come from in New Mexico's water?
Volcanic and geothermal geology throughout the Rio Grande Rift and Basin and Range province dominates arsenic occurrence in New Mexico. The Rio Grande Valley, Middle Rio Grande Basin, and surrounding volcanic highlands have documented arsenic at concentrations among the highest in the country. Communities from Taos through Albuquerque and south to Las Cruces draw from aquifer systems influenced by volcanic and geothermal chemistry.
What should New Mexico residents know?
New Mexico has had some of the highest rates of arsenic MCL exceedances of any state, particularly among small water systems in rural areas. Communities in Taos, Rio Arriba, Sandoval, Valencia, and Doña Ana counties have documented elevated arsenic. New Mexico NMED has worked extensively with small communities on arsenic treatment and has pursued grant funding to assist economically disadvantaged systems.
Key Facts
| EPA MCL | 10 µg/L (10 ppb) |
| MCLG | Zero |
| Primary source | Rio Grande Rift volcanic/geothermal geology — among highest naturally occurring arsenic states in U.S. |
| Historical compliance | New Mexico has had among the highest rates of arsenic MCL exceedances nationally |
| Environmental justice | Small, economically disadvantaged, rural Hispanic/Native communities face disproportionate exposure |
| State regulator | New Mexico Environment Department (NMED) |
| Health effects | Bladder, lung, skin cancer; cardiovascular; diabetes risk |
| Effective treatment | Activated alumina or reverse osmosis — both in widespread use at NM community water systems |
Why Arsenic Matters in New Mexico
New Mexico's arsenic problem is a function of the state sitting squarely atop some of the most arsenic-rich geology in North America. The Rio Grande Rift — a zone of crustal extension running from Colorado through New Mexico and into Mexico — is associated with volcanism and hydrothermal activity that has introduced arsenic throughout the regional aquifer system. The Albuquerque Basin, which supplies water to the state's largest metro area, has documented arsenic in deeper groundwater zones. Rural New Mexico communities, which are often small, economically disadvantaged, and Spanish-speaking, have faced disproportionate arsenic exposure challenges.
New Mexico Arsenic Program
New Mexico Environment Department monitors arsenic under federal SDWIS and recognizes New Mexico as one of the highest-arsenic states nationally. Volcanic geology throughout the state — the Jemez, Valles Caldera, and Rio Grande Rift — produces naturally elevated arsenic in groundwater. Many New Mexico small water systems required treatment after the 2006 MCL change. Private well owners across rural New Mexico should test for arsenic.
Largest New Mexico Water Utilities
No arsenic violations on record in EPA SDWIS for New Mexico utilities in our database. Browse the largest utilities to review their full water quality record.
How Does Arsenic Get Into Drinking Water?
Arsenic in drinking water is almost always naturally occurring — it leaches from arsenic-bearing rocks and minerals into groundwater over time. New England granite, Southwest volcanic geology, and Upper Midwest glacial aquifers are the primary high-risk formations. It has no taste, odor, or color.
Full arsenic overview — geology maps, health effects, all 50 statesWho Should Pay Closest Attention
Communities in Taos County, Rio Arriba County, Sandoval County, the Middle Rio Grande Basin (Albuquerque area deeper wells), Valencia County, and southern New Mexico's Doña Ana County face the highest arsenic risk. New Mexico's significant Hispanic and Native American rural communities face environmental justice dimensions of arsenic exposure.
Private well owners near mining districts or agricultural areas
Residents in states with documented volcanic or geothermal geology
Long-term consumers of water from small groundwater systems
Households in homes built before 1960 with older well casings
Residents whose well water has never been tested for arsenic
Anyone living in a state where bedrock wells are common
How to Check Your Situation in New Mexico
- 1
Identify your water source. If you use a public utility, use the ZIP lookup on this page to find your system and check its compliance record.
- 2
If on public water, review your utility's most recent Consumer Confidence Report (CCR) for arsenic monitoring data. The MCL is 10 ppb — your report should show recent test results.
- 3
If on a private well, order an arsenic test from a New Mexico Environment Department-certified laboratory. A basic arsenic test costs $15–$40. The state agency website maintains a certified lab list.
- 4
Test your well at the tap — not just at the wellhead. The entire water distribution system within your home can affect water quality.
- 5
If your test shows arsenic above 5 ppb, install certified treatment immediately. If above 10 ppb, do not use the water for drinking or cooking until treatment is installed.
- 6
Retest after installing treatment to confirm it is working as certified. Replace filter media on the manufacturer's schedule — an exhausted filter may not perform as rated.
Treatment Options for Arsenic
Boiling does not remove arsenic — it concentrates it. Standard activated carbon filters (Brita, etc.) do not effectively remove arsenic. Certified treatment is required.
NSF/ANSI Standard 58 — Reverse Osmosis
RO systems certified to NSF/ANSI 58 remove 85–95% of arsenic. Under-sink installation. Most effective for removing multiple contaminants simultaneously. Replace membranes and pre-filters on schedule.
Activated Alumina Filters
Activated alumina is specifically designed for arsenic and fluoride removal. Point-of-use or whole-house options available. Must be certified by NSF International or WQA for arsenic reduction. Requires periodic media regeneration or replacement.
Iron/Manganese Oxidation Filters
Effective for arsenic in iron-rich well water, which is common in the Midwest and New England. Oxidation converts dissolved iron and arsenic to a form that can be filtered out. Best when arsenic is co-occurring with high iron levels.
What does NOT work for arsenic
Standard activated carbon filters (Brita, refrigerator filters, most pitcher filters) do NOT effectively remove arsenic. Boiling concentrates arsenic. Water softeners do not remove arsenic. Only use products with NSF certification specifically for arsenic reduction.
Take Action Now
If you use a private well in New Mexico, test for arsenic — especially if you are in a region with granite, volcanic, or sedimentary geology. A basic arsenic test costs $15–$40 at a state-certified lab.
Public water users: check your utility's Consumer Confidence Report (CCR) for arsenic results. The EPA MCL is 10 ppb — any detection warrants attention.
If arsenic is detected above 10 ppb (or even below it, given MCLG is zero), install an NSF/ANSI 58-certified reverse osmosis system for drinking and cooking water.
Standard carbon filters do NOT remove arsenic — do not rely on a Brita or refrigerator filter for arsenic protection.
Frequently Asked Questions
Related Pages
Arsenic — National Overview
All U.S. utilities with arsenic records
New Mexico State Overview
All utilities and water quality data
New Mexico Well Water Guide
Testing, risks & certified labs for private wells
Reverse Osmosis Guide
Removes 85–95% of arsenic
Best Arsenic Filter Guide
What actually works (carbon doesn't)
PFAS in Drinking Water
The 'forever chemical' contamination overview
All Contaminants
Complete reference library
Data Sources & Provenance
All data on this page is sourced from official U.S. government or public datasets.
Find Your Utility
State Regulator
New Mexico Environment Department ↗