USGS Water-Quality Information
USGS personnel collect a water-quality sample on the Missouri River. USGS/Photo by Kelly Brady.
Water Quality Data
National Water Information System (NWIS)
NWIS provides current and historical water-quality data.
Today's Water Conditions
Water-Quality Watch provides continuous real-time water-quality measurements.
Water-Quality Web Services
Web services automate the sharing of USGS and USEPA water-quality monitoring data.
For More Data
Additional water-quality data resources are available.
USGS in Your Area
USGS Water Science Centers are located in each state.
Chapter A6. Field Measurements
The National Field Manual for the Collection of Water-Quality Data provides protocols, standard procedures, and guidance for U.S. Geological Survey (USGS) personnel who collect data used to assess the quality of the Nation's surface-water and groundwater resources. Chapter A6 presents general information and guidelines for performing field measurements (section 6.0) and specific requirements and guidance for collecting data for water temperature (section 6.1), dissolved oxygen concentrations (section 6.2), specific electrical conductance (section 6.3), pH (section 6.4), reduction-oxidation potential (section 6.5), alkalinity (section 6.6), turbidity (section 6.7), and for the use of multiparameter instruments in making such measurements (section 6.8). Each of these sections is revised periodically and published separately on this Web site.
Sections of Chapter A6:
6.1 Temperature (Version 2.0, 3/2006)
6.2 Dissolved oxygen (Version 3.0, 9/2013)
6.3 Specific electrical conductance (Version 1.2, 8/2005)
6.4 pH (Version 2.0, 10/2008)
6.5 Reduction-oxidation potential (electrode method) (Version 1.2, 9/2005)
6.6 Alkalinity and acid neutralizing capacity (Version 4, 9/2012)
6.7 Turbidity (Version 2.1, 9/2005)
6.8 Use of multiparameter instruments for routine field measurements (Version 1.1, 8/2007)
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For more information
Chapter 6 Archives
Archived versions for each section of Chapter 6 are linked to the html home page for the specific section.