San Marcos
Is San Marcos tap water safe to drink?
Mostly yes — San Marcos scores 87/100. This report aggregates EPA drinking water data across 3 local systems in San Marcos. We found 498 total violations (52 unresolved).
Real-Time Environment
Live: 03:15 PM☀️ No active precipitation. Rainfall can impact surface water turbidity and pollutant runoff in San Marcos.
Water Quality Impact
🛡️ Home Water Treatment Needs
Should you invest in filtration or softening for your home in San Marcos?
Expert Advice
Your water quality is excellent. Standard filtration is optional but can further enhance taste.
Buying a Filter?
Wondering if San Marcos tap water needs filtering? We break it down.
Baby Formula Safety
Mixing baby formula with San Marcos tap water? Read this first.
Homebuyer's Perspective
If you're house-hunting in San Marcos, water quality belongs on your due-diligence checklist alongside schools and crime data. The high safety score (87/100) suggests lower risk for plumbing corrosion and appliance scaling.
Health & Family Safety
Residents should monitor Lead (90th percentile) levels. Pregnant women and families with young children should consult the specific EPA health goals listed below.
View Health Risk Glossary →Compliance Record for San Marcos
Based on EPA SDWIS violation records and contaminant test results for all water systems serving San Marcos.
Frequently Asked Questions
Is San Marcos tap water safe to drink?
Mostly yes — San Marcos scores 87/100.
How many water systems serve San Marcos?
San Marcos is served by 3 public water systems in our latest EPA-backed dataset.
How can I check water quality for my exact address in San Marcos?
Use the WaterQ search tool to look up your ZIP code and view nearby systems, contaminant levels, and recent violations for San Marcos.
What is the water quality score for San Marcos?
The water quality score for San Marcos is 87 out of 100, based on EPA contaminant data, violation history, and testing results across the 3 systems serving the city.
What are the top contaminants in San Marcos?
The top contaminants detected in San Marcos include Lead (90th percentile). View detailed information on our contaminants page.
San Marcos Water Quality Summary
San Marcos, TX receives a water quality score of 87/100 (Grade B) based on EPA Safe Drinking Water Information System (SDWIS) compliance data for 3 public water systems serving the area.
San Marcos's water quality is above the national average, with strong compliance records and low contaminant levels. Residents generally receive clean, safe tap water that meets EPA standards.
San Marcos's score of 87 is 11 points above the Texas state average of 76, and above the nationwide average of roughly 78/100 across all U.S. states.
Prospective homebuyers looking at San Marcos will find that this mid-size Texas city provides excellent tap water quality across its various local supply systems. This high level of cleanliness is especially impressive given the geological complexities of South-central Texas and the regional prevalence of large urban hubs and oil and gas activity. Ultimately, residents can go about their daily routines with verified regulatory compliance regarding the safety and management of their household water.
Water quality data is sourced from the U.S. EPA SDWIS database and updated quarterly. Learn about our scoring methodology → Read our Texas water quality rankings report →
Key Contaminants
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Water Systems Serving San Marcos (3)
Check Your Specific Address
Water quality can vary by neighborhood in San Marcos.
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