An official website of the United States government
Here's how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Latest Earthquakes | Live WebChat Share Social Media
This focuses on how we use groundwater age to predict changes in nitrate concentrations over time. Typically, deep public supply wells draw from deeper parts of the aquifer where water is decades, centuries, or even millenia old.