Tap water in San Marcos, TX — ZIP 78666
4 public water systems serving about 153,392 people. PFAS "forever chemicals" have been detected here.
F
Failing
PFAS detected: at least one system serving this ZIP reported PFAS in EPA UCMR 5
testing. Levels and the 2024 federal limits are shown per system below.
Water systems serving 78666
City Of San Marcos
PWSID TX1050001 · serves 72,970 ·
surface water
1 health-based / 1 total violations (5 yrs)
· PFAS up to 11.4 ppt
Texas State University - San Marcos
PWSID TX1050003 · serves 43,552 ·
groundwater
0 health-based / 1 total violations (5 yrs)
Crystal Clear Sud
PWSID TX0940015 · serves 20,766 ·
surface water
0 health-based / 2 total violations (5 yrs)
· PFAS up to 5.6 ppt
Maxwell Sud
PWSID TX0280003 · serves 16,104 ·
surface water
15 health-based / 19 total violations (5 yrs)
· PFAS up to 3.8 ppt
Grades summarize EPA SDWIS violation records (last 5 years) and UCMR 5 PFAS results. They are informational, not a health determination. Methodology