Which areas in the United States are most dependent on groundwater?

Map of groundwater withdrawals by U.S. state in 2010. Image Credit: U.S. Geological Survey

Groundwater use is highest in parts of the country with limited rainfall but high water needs, especially for irrigation purposes. Most of these areas are in the western half of the country, where annual rainfall is typically much lower than in the East and where surface water supplies cannot meet the demand for water.

In 2010, groundwater provided 25% of the total freshwater used in the United States. However, nine states depended on groundwater for at least 50% of their freshwater supply[1]:

Kansas 80%
Arkansas 69%
Mississippi 68%
Florida 64%
Hawaii 63%
Nebraska 59%
Alaska 55%
South Dakota 54%
Delaware 52%

Some of the states listed above have small populations and/or limited irrigation needs (e.g. Alaska, Hawaii, and Delaware), so their absolute groundwater needs are relatively small. The states that use the largest total volumes of groundwater tend to have large populations and/or extensive farmland in arid areas. In 2010, just five states accounted for 47% of national groundwater use, mostly for irrigation[1]:

California 16%  (68% for irrigation)
Arkansas 10%  (95% for irrigation)
Texas 10%  (66% for irrigation)
Nebraska   6%  (91% for irrigation)
Idaho   5%  (90% for irrigation)

References

1 Estimated Use of Water in the United States in 2010 U.S. Geological Survey

Learn More:

  • Ground-Water Availability in the United States (Report), U.S. Geological Survey
    2008 report assessing national availability of groundwater. Written for a wide audience of people interested in management, protection, and sustainable use of U.S. water resources
  • Ground Water Atlas of the United States (Book/Website), U.S. Geological Survey
    2000 atlas showing and describing the principal aquifers across the United States, including hydrologic and geologic information
  • Managed Aquifer Recharge (Factsheet), American Geosciences Institute
    Introduction to managed aquifer recharge, including how it works and its effects on water quality and availability
  • Desalination as a Source of Fresh Water (Webinar), American Geosciences Institute
    Webinar on the use and desalination of salty water, including brackish groundwater, in the United States and further afield.