Connecticut Water Use

Science Center Objects

Background: The U.S. Geological Survey has compiled the Nation's water-use data at the county, State, and national levels every 5 years since 1950. The most recent estimated water-use compilation was completed in 2015. A summary for Connecticut is presented on this web page.

The Issue: Comprehensive water-use data analysis is needed to quantify the stress on existing supplies, particularly during periods when there is increased competition for water (for example, periods of drought).


- USGS water-use compilations are one of the few sources of information about national and regional trends in water withdrawals. 

- The New England Water Science Center (WSC) collects, reviews, and aggregates water withdrawal data in Connecticut from different sources (groundwater and surface water in both fresh and saline settings) as a part of the national effort.

- Our WSC collects site-specific and aggregated water-use information for each county in Connecticut. 

- The New England WSC complies and estimates water use at the county level for eight water-use categories: thermoelectric, public supply, domestic, livestock, mining, industrial, irrigation, and aquaculture.

Water Issues

Connecticut is fortunate to have abundant freshwater resources.

Annual precipitation averages in Connecticut place the State in the top half of the wettest States in the United States.

However, as populations have grown (9.1 percent between 1990 and 2015), freshwater resources have come under significant stress in many areas, particularly during periods of drought.

Connecticut population trends, 1990 - 2015

A graph showing Connecticut population trends between 1985 and 2015. (Public domain)

Connecticut water withdrawal trends, 1990 - 2015

A graph showing Connecticut water withdrawal trends between 1990 and 2015. (Public domain)

Summary of 2015 Compilation 

Core numbers for Connecticut are presented in the Results tab.


How Much Water is Used in Connecticut?

In 2015, approximately 3,128 million gallons per day (Mgal/d) of water was withdrawn from groundwater and surface-water sources in Connecticut. Total water withdrawals between 1990 and 2015 are on steady decline (-35 percent).

  • Surface water withdrawals totaled 3,000 Mgal/d (96 % of total) 
  • Groundwater withdrawals totaled 128 Mgal/d (4 % of total)
  • Freshwater withdrawals were 617 Mgal/d (20 % of total)
  • Saline water withdrawals were 2,511 Mgal/d (80 % of total)

Connecticut Total Water Withdrawals in 2015 by Category (Values in Mgal/day)

  • Thermoelectric—2,593
  • Public Supply—240
  • Industrial—222
  • Domestic—31
  • Aquaculture—25
  • Irrigation—11
  • Mining—4
  • Livestock—1
Connecticut Total Water Use by category in 2015

Connecticut total water use by category in 2015. (Public domain)

Animation of 2015 Connecticut water use by category

Animation of 2015 Connecticut water use by category, captured from the visualization of 2015 United States water use by category, by the USGS Vizlab. (Public domain)

Connecticut Public Water Supply Withdrawals in 2015 by County

CT CountyGroundwater (Mgal/d)Surface Water (Mgal/d)Total (Mgal/d)
New Haven4.7749.7254.49
New London2.255.868.11