Sprinklers water a patch of grass on the sidewalk in front of a house in Alhambra, California, on July 25, 2014. In the latest report released by the California Department of Water Resources on July 23, ten of the state's 12 major reservoirs have fallen below 50 percent of their total capacity as California nears the historic lows set in 1977, with reservoir levels expected to further drop if the three-year drought persists. And despite calls from California Governor Jerry Brown to limit water use during drought, a report released last week by the State Water Resources Control Board showed Californians have actually increaded water consumption this year. AFP PHOTO/Frederic J. Brown (Photo credit should read FREDERIC J. BROWN/AFP/Getty Images)

SACRAMENTO, Calif., Sept 10 (Reuters) - Facing acute water shortages in some communities and mandatory restrictions on watering lawns, Californians saved 17 billion gallons of water in July, enough to fill 26,000 Olympic-sized swimming pools, the state said.

The amount saved falls short of the 20 percent reduction in use called for by Democratic Governor Jerry Brown, but represents significant cutbacks in water use as the most populous U.S. state struggles through its third year of a devastating drought.

"Every action, from taking a shorter shower,to putting a lawn on a water diet, to replacing turf with drought-tolerant landscaping, contributes to every community's water security," Felicia Marcus, chair of the State Water Resources Control Board said Tuesday.

California is in its third year of a devastating drought that has forced farmers to leave fields unplanted and left communities reliant on well water with little to drink.

The data released Tuesday is the first monthly information on water use gathered by the state since it began requiring local water agencies to file monthly conservation reports earlier this summer.

It showed that overall, Californians cut water use by about 7.5 percent over July of 2013.

In some communities, including stricken regions in the northern part of the state, consumers and businesses saved far more than that, cutting consumption by half over last year, the water board said.

Overall, the water saved was enough to for 1.7 billion people to each take a five-minute shower, the state said.

The mandatory conservation measures forbid such actions as letting sprinklers drench driveways and concrete walkways while watering the lawn, using a hose without a shut-off valve to wash a car and using drinkable water in fountains that do not recirculate it.

Some communities have banned residents from filling their swimming pools, and in Southern California, residents have removed 2.5 million square feet of turf from their front and back yards, replacing water-thirsty grass with drought tolerant plants and other landscaping.

Marcus called for still more conservation as the drought drags on.

"Wasting precious potable water today imperils our communities' future," she said.