Tap water in Williamstown, MO — ZIP 63021

2 public water systems serving about 1,119,000 people. PFAS "forever chemicals" have been detected here.

Excellent

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 63021

Mo American St Louis St Charles Counties

PWSID MO6010716 · serves 1,111,000 · surface water

0 health-based / 0 total violations (5 yrs) · PFAS up to 5.1 ppt

Clark County Cons Pwsd 1

PWSID MO2024138 · serves 8,000 · groundwater

0 health-based / 2 total violations (5 yrs)

Grades summarize EPA SDWIS violation records (last 5 years) and UCMR 5 PFAS results. They are informational, not a health determination. Methodology