USGS California Water Use Estimate Released Early, Shows Drop in Overall Water Use

Gage Canal and Folsom Windsor Pump House

Late August 2014, the United States Geological Survey (USGS) released its 2010 California water use estimate, the latest in the series of 5-year reports it has compiled since 1950. This installment was slated to be released later in 2014, but it was published early to satisfy increased interest in water use prompted by the drought.

Continuing a 30 year-old trend, overall water usage fell between 2005 and 2010, going from 46 billion gallons per day to 35 billion gallons per day.  All of the savings came from reduced withdrawal of surface water, which dropped by 10 billion gallons per day to 25 billion gallons per day.  Groundwater usage, on the other hand, ticked up from 11 billion to 13 billion gallons per day, accounting for one third of the state’s total consumption.  Finally, 18.1% of the water used in the state was saline, almost all of which went to generating electricity.

The report also measures the state’s water usage by category.  At over 23 billion gallons per day (60.7%), irrigation accounted for the majority of daily water use.  If only fresh water is considered, irrigation’s share of daily use rises to 74%.  Public supply represents about 16% of daily usage, with Californians averaging 181 gallons per day per person.  People who supply their own water use about 69 gallons per day per person, and make up 0.5% of the state’s total usage.

Finally, the USGS report provides a county-by-county breakdown of the data, demonstrating the variety of sourcing and usage across the state.  For instance:

  • Los Angeles County used about 3 billion gallons/ day, with 71% coming from surface water. About 90% of the county’s water went to public supply and electricity generation, each in roughly equal amounts.
  • San Bernardino County used 659,400 gallons/day, 82.7% from the ground, and used 71% of its water for public supply.
  • Yolo County used 780.2 million gallons/day. 5% came from surface water.  735.5 million gallons/day (94.5% of total use) went to irrigation, with almost all the rest used for public supply
  • San Diego County used 2.818 billion gallons/day, 96.9% from surface water sources. 76% of the water used in the county went to thermoelectric power generation, with public supply and irrigation accounting for most of the balance.
  • Imperial County used 1.169 billion gallons/day, 96.9% from surface water. 93% of the water went to irrigation.
  • Sacramento County used 681 million gallons/day, 53.7% from surface water. 90% went to public supply and irrigation, with industrial and aquaculture uses making up most of the balance.
  • Kings County used 1.251 billion gallons/day, 58.3% from surface water. Irrigation accounted for 96% of total usage, with most of the rest going to public supply (2.2%) and livestock (1%).

Read the complete report here.

Written by Stratecon Staff