01The verdict: is San Antonio water safe?
San Antonio's drinking water has significant quality concerns based on EPA testing data. With a grade of B+ (83.9/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 1,344 residents using groundwater (wells).
7 unresolved violations on record
EPA records show open compliance items for this system. Most are administrative, but unresolved items are worth watching.
See what was cited ↓Lead is well under the limit
90th-percentile lead is 2.0 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.
See the trend ↓5 violations in the last five years
Recent compliance history is the best predictor of future problems — the year-by-year record is below.
See the record ↓San Antonio's drinking water received a grade of B+ (83.9 out of 100), indicating good water quality. The city's 1 water system serves approximately 1,344 residents using groundwater.
Lead levels were measured at 2.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program. The system has 15 violations on record, including 1 health-based violation. 7 remain unresolved.
San Antonio ranks #18 out of 153 cities in New Mexico for water quality, placing it above average in the state. San Antonio relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff. As a small community water system, San Antonio may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in San Antonio's water
Every contaminant flagged in San Antonio, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 2.0 | 15 | ppb | Inorganic | Safe |
Cities ranked by 90th-percentile lead PF PFAS in New Mexico
Cities ranked by compounds detected Cu Copper in New Mexico
Cities ranked by 90th-percentile copper
03San Antonio's ten-year track record
Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 15 violations on record, including 1 health-based violation. 7 remain unresolved.
4 of the last ten years were clean. The numbered years had EPA violations — red when any were health-based, amber when they were paperwork or missed-testing issues.
▲ Up 2 ppb since 2005. Latest reading: 2 ppb (2024) — 13% of the action level. Sampled at higher-risk homes (90th percentile).
04Where San Antonio's water comes from
San Antonio's drinking water is drawn from underground aquifers through wells.
Groundwater
Underground aquifers reached by wells — naturally filtered, but can carry minerals like arsenic and nitrate.
Local treatment
Groundwater generally needs less treatment — typically disinfection and, where needed, mineral removal.
1 system
1 water system, operated under local government ownership.
1,344 people
Residents served across San Antonio's service area.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals. Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds. The system is operated by local government ownership and serves approximately 1,344 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| SAN ANTONIO MDWCA | NM3573928 | 1,344 | Groundwater |
Water bodies near San Antonio
These water bodies shape the regional watershed and can indirectly affect groundwater quality.
05Pressure on San Antonio's watershed
Outside forces that shape what reaches the treatment plant. None of these is a verdict on the tap by itself — but each adds pressure worth knowing about.
Flood & storm history
3 federal disaster declarations on record for Socorro County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
Drought
Socorro County is in D3 (extreme drought) per the U.S. Drought Monitor (week of Jul 2026). Drought can raise disinfection-byproduct levels and taste/odor issues as utilities draw from lower reservoirs.
06How San Antonio compares
Scores for nearby New Mexico cities on one line, with the average marked.
dashed line = New Mexico average (49/100)
San Antonio scores 83.9/100 — above the New Mexico average of 49/100. It outscores 9 of 10 nearby cities. Full New Mexico rankings →
40.2 / 100FLas Cruces, NM
40.1 / 100FSanta Fe, NM
35.7 / 100BRio Rancho, NM
83.8 / 100DRoswell, NM
45.8 / 100FFarmington, NM
40.4 / 100
Compare all cities in the county — grades, violations, and contaminant data side by side.→
07What to do at home
Steps matched to what testing actually found in San Antonio's water — not generic advice.
A basic carbon filter still helps
San Antonio's water meets federal standards, but a simple carbon filter improves taste and adds a margin of safety against short-term issues.
Compare tested filters →Read your utility's annual report
Every utility must publish a yearly Consumer Confidence Report with its own testing results. It pairs well with the independent data on this page.
How to read a CCR →Watch for San Antonio alerts
This area has a history of flood declarations — after severe weather, watch for boil-water advisories from the utility, and check the live alerts on this page.
All water alerts →Frequently asked questions
Is San Antonio, NM tap water safe to drink?
San Antonio's water quality earned a grade of B+ (83.9/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #18 out of 153 cities tested in New Mexico.
What contaminants are in San Antonio's water?
Lead was measured at 2.0 ppb (90th percentile). 15 violations are on record.
How is San Antonio's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in San Antonio?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does San Antonio's water come from?
San Antonio's water is sourced from Groundwater. The city has 1 water system serving approximately 1,344 residents.
What health violations has San Antonio's water system had?
San Antonio has 1 health-based violation on record. The most recent violation was recorded in January 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 7 violations remain unresolved.
Is San Antonio's groundwater at risk of contamination?
San Antonio uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 15 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does San Antonio's water compare to other cities?
San Antonio ranks #18 out of 153 cities in New Mexico (better than 88% of state cities) and #6143 out of 15382 cities nationally (60th percentile). The grade of B+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does San Antonio's small water system affect quality?
San Antonio's system serves approximately 1,344 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 15 violations on record.