The latest figures on water use in the United States show that conservation efforts are having an impact.

A new report published by the U.S. Geological Survey (USGS) reveals that the volume of water used across the country has reached its lowest recorded level in nearly 45 years.

About 355 billion gallons of water per day (Bgal/d) were withdrawn for use in the entire United States during 2010. That's a decrease of 13 percent from 2005 when about 410 Bgal/d were withdrawn.

The news was welcomed by the U.S. Department of the Interior.

"Reaching this 45-year low shows the positive trends in conservation that stem from improvements in water-use technologies and management," commented Mike Connor, deputy secretary of the Interior.

Connor pointed out the reduction comes at a time when the U.S. population is continuing to grow, and demonstrates that people are learning to be more water conscious and helping to sustain the limited freshwater resources in the country.

Water withdrawn for thermoelectric power represented the largest use nationally in 2010. The other leading uses were irrigation, public supply and self-supplied industrial water. Withdrawals declined in each of these categories, USGS said.

Thermoelectric power recorded a 20 percent decrease from five years earlier as a result of more efficient cooling-system technologies, declines in withdrawals to protect aquatic habitat and environments, power plant closures and a reduction in the use of coal to fuel power plants.

Looking at industrial withdrawals, the 12 percent decrease since 2005 was put down to factors such as greater efficiencies in industrial processes, more emphasis on water reuse and recycling, and the 2008 U.S. recession, which resulted in lower industrial production in major water-using industries.

Overall, more than half of the total water withdrawals in the United States were accounted for by 12 states: California, Texas, Idaho, Florida, Illinois, North Carolina, Arkansas, Colorado, Michigan, New York, Alabama and Ohio.