Water for Long Island: Now and for the Future

Fact Sheet 2019-3052
Prepared in cooperation with the New York State Department of Environmental Conservation
By:  and 



Do you ever wonder where your water comes from? If you live in Nassau or Suffolk County, the answer is, groundwater. Groundwater is water that started out as precipitation (rain and snow melt) and seeped into the ground. This seepage recharges the freshwater stored underground, in the spaces between the grains of sand and gravel in what are referred to as aquifers. Long Island has three primary aquifers—the upper glacial, Magothy, and Lloyd—which are part of the Long Island aquifer system. Currently [2019], this aquifer system contains about 50 trillion gallons of freshwater.

Suggested Citation

Masterson, J.P., and Breault, R., 2019, Water for Long Island—Now and for the future: U.S. Geological Survey Fact Sheet 2019–3052, 2 p., https://doi.org/10.3133/fs20193052.

ISSN: 2327-6932 (online)

ISSN: 2327-6916 (print)

Study Area

Table of Contents

  • Do You Ever Wonder Where Your Water Comes From?
  • Why Is Groundwater Important?
  • Why Is Saltwater Intrusion a Concern?
  • What Are Other Groundwater Quantity and Quality Concerns?
  • How Is the U.S. Geological Survey Assessing Groundwater Sustainability?
Publication type Report
Publication Subtype USGS Numbered Series
Title Water for Long Island: Now and for the future
Series title Fact Sheet
Series number 2019-3052
DOI 10.3133/fs20193052
Year Published 2019
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) New York Water Science Center
Description 2 p.
Country United States
State New York
Other Geospatial Long Island
Online Only (Y/N) N
Google Analytic Metrics Metrics page
Additional publication details