Reporting from San Luis Obispo, Calif. — Katie Martin grew up with a set of water commandments. No lingering in the shower. Turn off the faucet when you brush your teeth. Don't flood the yard.
Until she left for college this fall, the 19-year-old lived with her family in a typical California stucco house with a lawn. But when it comes to water, neither the Martins nor their town, San Luis Obispo, is typical.
Katie, her parents and little brother use roughly half the water on a per-person basis as the average single-family household in Los Angeles used last year.
"The community is just like that," Martin said.
As climate change, environmental constraints and growth continue to tighten the valve on California's water supplies, the rest of the state is going to be more like that too. Not just during droughts but all the time.
The reason is simple. Compared to building new reservoirs, recycling or seawater desalination, conservation is one of the cheapest, quickest and least environmentally damaging ways for the state to get more water.
"I think we have a water crisis in California, and I think conservation is the only solution that can be implemented in time," said Kevin Wattier, general manager of the Long Beach Water Department.
Water demand in Southern California has remained essentially flat the last two decades, despite the addition of 3.7 million people.
Similarly, L.A. used slightly less water last year than in 1990, even though there are a million more Angelenos now.
Much of the lid on demand has been achieved through gadgetry. Utility rebates and plumbing ordinances have put low-flow toilets and shower heads in millions of buildings and homes. Water agencies promote high-efficiency washing machines.
But it hasn't been enough, said Timothy Brick, chairman of the Metropolitan Water District of Southern California, the region's water wholesaler. "I think we have a long way to go."
Ramping up the Southland's conservation efforts could save more water annually than the combined demand of Los Angeles, San Diego and Long Beach, his agency estimates.
Gov. Arnold Schwarzenegger last year called for the state to cut urban per-capita water use 20% over the next decade. Wide-ranging water legislation approved this month in Sacramento mandates the drop.
"It can be done. But people have to want to do it," said UC Berkeley professor Michael Hanemann, director of the university's California Climate Change Center. "Urban water agencies have to get religion."
San Luis Obispo got religion during the drought of the late 1980s and early 1990s, when the town's main water source, a reservoir on the Salinas River, shriveled to a big pond rimmed by dried mud.
"It was very, very scary. We had mandatory rationing, penalties," recalled Gary Henderson, a manager in the city Utilities Department.
Water use plummeted. By the drought's end, San Luis Obispo had learned its lesson. Conservation was the new normal.
So frugal are the town's water ways that this year it has not had to resort to the emergency water restrictions that Los Angeles and other cities adopted to deal with the current drought.
Home to Cal Poly San Luis Obispo, the community leans green. Partly to control growth, residents in 1992 voted against tapping into the State Water Project, which would have given them access to supplies from Northern California.
All their water comes from the Central Coast, and with it comes a sense of permanent limits.
"You don't want to waste that resource," said Hal Hannula, a civil engineer who works for the city and grew up in nearby Morro Bay. "I think I'm fairly typical."
The Hannulas ripped out the lawn in their backyard themselves and replaced it with pea gravel, flagstone and flower beds irrigated with drip lines.
"We're down to that last piece in the front, which we're threatening to remove," Hannula says, eyeing a small green rectangle of grass.
The family's dishwasher and clothes washer are high water-efficiency models. He and his wife, Kelly, have considered installing a timer or shut-off valve in the shower to keep their teenagers from loitering there.
With one of their four children, 17-year-old Matthew, living at home full time during the past year, the Hannulas' daily water use amounted to a mere 58 gallons per person.
That beats San Luis Obispo's overall residential average. And it is a fraction of the averages in some desert and Central Valley towns, where per-capita household use topped 200 and even 300 gallons a day last year. Los Angeles' single-family home use averaged 117 gallons.
The big frontier is outdoor watering, which the state estimates accounts for half of all urban potable water use. In California's hottest regions, as much as 70% of the water piped to single family homes is hosed and sprinkled outdoors.
Changing that could be the toughest conservation sell of all.