National Tap Water Database · 2025 Edition
What's really in
your tap water?
Legal doesn't always mean safe. Search your Zip Code to see the contaminants in your local water supply — and what to do about them.
Data compiled from official EPA & USGS environmental monitoring databases.
Try or
170M+
Americans exposed to forever chemicals (PFAS)
320+
Contaminants detected in US tap water systems
50,000
Utilities monitored across all 50 states
How it works
Three steps to clean water clarity
STEP 01
Enter your Zip Code
We match your address to the EPA-registered water utility that serves you.
STEP 02
Review your report
See every detected contaminant with its level, the health guideline, and the legal EPA limit side by side.
STEP 03
Get a filter plan
Receive a personalized filtration recommendation matched to the specific contaminants in your water.
Trusted by families & professionals
What our users are saying
"I had no idea our tap water exceeded the health guideline for arsenic by 8x. US Water Guidelines gave me a plain-English breakdown and an action plan in seconds."
Sarah Whitman
Mother of two · Austin, TX
"I now send every patient family to this database. Legal limits aren't health limits, and parents deserve to see that distinction clearly."
Marcus Reed
Pediatrician · Columbus, OH
"The data density is exactly what serious users need. Source attribution, multipliers over health guidelines, and filtration recommendations all in one view."
Elena Garcia
Environmental researcher · Boulder, CO