With mountain water supply below a 40-year average, the Nevada Irrigation District is tapping into reserves to keep water flowing to 24,500 customers who depend on it for drinking and irrigating crops, officials said.

Water storage is at about 75 percent of capacity in upper division reservoirs such as Bowman Lake and Jackson Meadows - about 13,000 acre feet below a 40-year average.

"Inflow into the reservoirs is virtually zero," said NID general manager Don Nelson. "We're primarily working on reserves right now."

Despite the lower water supplies, the shortage is not enough to hamper deliveries, said NID operations manger Don Wight. The amount of water missing from reservoirs this year is enough to supply 4,500 homes for a year.

In an average year the district holds 200,000 acre feet in its reservoirs, compared with 186,972 this year. One acre foot amounts to one acre covered one foot deep with water.

The water district is faring better then the rest of the state in one of the worst droughts on record.

A dry spring and low snow pack has forced some water agencies in the Sacramento Valley and southern parts of the state to pose strict water rationing. Lawmakers have called for more water storage and dams.

So far, NID has not imposed mandatory water conservation but has begun a water efficiency program this year, providing free consultation to big water users, such as vineyards and schools.

A landscape irrigation consultant from Roseville provided tips to participating schools on how to reduce water consumption by 15 percent by fixing leaks, adopting less frequent watering schedules and using more efficient sprinkler heads.

This fall, NID will purchase water normally allowed to run downstream for hydroelectric use by Pacific Gas & Electric Co.

"That will allow us to retain water in upper storage," Wight said.

With the threat of climate change, the district needs to look at obtaining additional water rights and developing more water storage, said Nick Wilcox and Brad Fowler, two candidates running for the board of directors division 5 seat in November.

"The Yuba watershed is not fully appropriated," Wilcox said.

Taking more water from the South Yuba River could unsettle people who are working to bolster instream flows for fish habitat.

Looking for more water storage is something the water agency is not actively looking at now, Wight said.

To contact Staff Writer Laura Brown, e-mail lbrown@theunion.com or call 477-4231.