The historic drought is making average residents think twice every time they turn on the tap, despite the weekend rain. But there is nothing average about the way Californians consume water: A little-known state database that measures water use in every community shows huge — sometimes shocking — differences between California’s water sippers and guzzlers.

In steamy Sacramento, where half of the homes still don’t have water meters, residents use 279 gallons a day per capita — almost triple the 98 gallons that residents of foggy San Francisco use. Palm Springs, land of big desert lawns and verdant golf courses, gulps down a staggering 736 gallons a day per person, five times as much as residents of San Jose and Los Angeles.

The Golden State’s varied climate plays a key part in how much water a city or town consumes, as does the density of its population. But the differences can be stark even among close neighbors.

The largest per-capita water user in the Bay Area is Hillsborough, a tony Peninsula town where residents average 334 gallons a day. Only 14 miles away, working-class East Palo Alto residents use less than a quarter as much — 79 gallons a day.

“There are things like differences in yard sizes, but quite frankly — this is something most people don’t want to admit — if you are in a wealthier community, people tend to use more water because it is inexpensive for them,” said Chris Brown, former executive director of the California Urban Water Conservation Council, a Sacramento nonprofit.

Landscaping, which accounts for 50 percent of the typical residential water bill, is a driving factor.

In Hillsborough, ornate bushes and towering hedges fence in lush, green lawns and winding brick driveways that lead to three-story houses with views of San Francisco Bay. Vegetation bleeds into the streets, where miniature shrubs adorn sidewalks and flower patches embellish four-way stops.

“Everyone cares that their frontyard and backyard looks pretty,” said Patsy Leung, a Hillsborough resident. “But it takes water.”

In densely populated East Palo Alto, some homes have well-maintained lawns, but other frontyards are covered with cement, stones, dried-out grass, withered shrubs and perhaps a few floppy palm trees.

“We’re cutting back on showering and watering our lawn — so it looks crappy right now,” said Gerald Dow, an East Palo Alto resident who’s determined not to waste water during the drought.

Lawns tell only part of the story found among the per-capita usage figures that are tucked away in a state Department of Water Resources database in Sacramento. Under state law, every water provider, from cities to water districts, is required to report its per-capita use, as well as to come up with plans to cut back during droughts and reduce consumption by 20 percent by 2020.

The figures also offer clues as to who is doing best at conservation.

“Even taking into account differences in weather and demographics, these numbers show there has been widely divergent success and failure on water efficiency,” said Peter Gleick, president of the Pacific Institute, an Oakland nonprofit group that studies water use. “Some water agencies have done a lot more than others in encouraging more efficient use of water.”

In the East Bay, where summer temperatures regularly hit 100 degrees, the Contra Costa Water District reports 183 gallons per capita, for example, less than the state average of 196 gallons per day.

The district offers free water audits to residents and rebates for people who buy water-efficient toilets and appliances or replace lawns with drought-tolerant plants.

“We’ve had conservation programs in place for decades,” said Jennifer Allen, a spokeswoman for the district. “But we can always do more.”

To arrive at the per-capita totals, each water provider added up all residential, government and business use and divided by population over a consecutive 10-year period they chose between 1995 and 2010. The totals do not include agriculture, which uses 80 percent of the water that people consume in California.

In addition to the clear difference in water usage between rich towns and poor towns, a review of the 355 cities and water districts in the database shows other patterns:

Places with hot weather tend to use the most water. Coastal cities, which enjoy cooler summers and lots of fog, consume relatively little. Santa Cruz residents use only 113 gallons per capita per day. Crescent City, a fishing town near the Oregon border, averages only 97 gallons a day. But in the Central Valley, Inland Empire and Southern California desert areas, where the blazing summer sun requires more water use on landscaping, residents use three or four times that much. In Riverside County, customers of the Coachella Valley Water District use 591 gallons per capita per day.