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.
The U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL) conducts methods to measure physical properties in environmental samples. These analyses include color, pH, specific conductance, alkalinity, and dissolved and suspended solids.