Groundwater Quality Research

Featured Study: Simple method to classify groundwater age

Featured Study: Simple method to classify groundwater age

A new USGS report documents a simple method to classify groundwater age as premodern (recharged before 1953), modern (recharge in 1953 or later), or a mix of the two. Just a single tritium measurement needed!

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Featured Study: Temporal Variability of Arsenic in Groundwater

Featured Study: Temporal Variability of Arsenic in Groundwater

new USGS study investigates how concentrations of arsenic in three drinking-water supply wells change at daily, seasonal, and yearly time scales. Arsenic variability and related factors identified have potential implications for human health.

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Every day, millions of gallons of groundwater are pumped to supply drinking water for about 140 million people, almost one-half of the Nation’s population. Learn about the quality and availability of groundwater for drinking, where and why groundwater quality is degraded, and where groundwater quality is changing.

Groundwater is our invisible, vital resource. The USGS National Water Quality Program (NWQP) is focusing on studies of principal aquifers, regionally extensive aquifers that are critical sources of groundwater used for public supply. The studies have two main thrusts:

Collecting groundwater data

Collecting groundwater data

  • Current conditions and changes through time. These assessments characterize groundwater quality in principal aquifers, comparing concentrations of inorganic constituents, such as arsenic and nitrate, and organic constituents, such as pesticides and volatile organic compounds, to benchmarks established for the protection of human health.  Tracking changes in groundwater quality through time and investigating the reasons for these changes is crucial for informing management decisions to protect and sustain our valuable groundwater resources.  See how concentrations of metals, nutrients, pesticides, and organic contaminants in groundwater are changing during decadal periods across the Nation, and view real-time fluctuations in groundwater quality.
  • Predicting groundwater quality. Statistical models and 3-D characterizations predict where a contaminant is likely to occur in groundwater, at what depth, and at what concentration. These forecasts anticipate water quality in areas where groundwater has not been sampled.

From 1991 to 2010, about 6,600 wells were sampled by the NWQP to document where contaminants occur and to develop an understanding of the natural and human factors that affect the occurrence of contaminants in the Nation’s groundwater. Learn about groundwater quality in the Nation’s principal aquifers, 1991–2010.


Explore USGS science on topics related to groundwater quality:

National Water Quality Assessment (NAWQA) Project

Contaminants in groundwater
     Chloride and salinity
     Emerging contaminants
     Volatile organic compounds (VOCs), including MTBE
     Hydraulic fracturing

Drinking and source-water quality
     Domestic (private) supply wells
     Public-supply wells
     Drinking-water taste and odor
     Water-quality benchmarks     

Processes affecting groundwater quality
     Groundwater age dating

How do we do it?  Access USGS publications and manuals on sample-collection methods.

Looking for information on surface-water quality as well?  Explore these links:
     Surface-Water Quality and Ecology
     Surface-Water/Groundwater Interaction