Connecticut Water Use

Science Center Objects

Background: The U.S. Geological Survey compiles estimates of water use in Connecticut and the rest of the United States 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 webpage.

The Issue: Comprehensive water use data analysis is needed to quantify the stress on existing supplies, specially during the increasing competition for water (e.g. periods of drought).


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

- The New England WSC collects, reviews, and aggregates water withdrawal data from different sources (groundwater, surface water, fresh and saline) in Connecticut 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 estimates water use at the county level for eight water use categories: thermoelectric, public, domestic, livestock, mining, industrial, irrigation, and aquaculture.

Water issue

Connecticut have been gifted with abundant freshwater resources.

Annual precipitation averages in Connecticut place the state in the top half of the wettest states in the US.

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

Connecticut population trends, 1990 - 2015

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)

2015 compilation outcome 

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In 2015, approximately 3,128 million gallons per day (Mgal/d) of water was withdrawn from groundwater and surface-water sources in Connecticut.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%).

  • Surface water withdrawals totaled 3,000 Mgal/d (about 96 percent of total) 
  • Groundwater withdrawals totaled 128 Mgal/d (about 4 percent of total)
  • Fresh water withdrawals were 617 Mgal/d (about 20 percent of total)
  • Saline water withdrawals were 2511 Mgal/d (about 80 percent 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