The California swimming pool and spa industry has launched a campaign to market itself as a drought-friendly landscaping option as the state enters a fourth summer of drought that has residential pools and other conspicuous water users in the crosshairs.

As residents struggle to reduce potable water consumption by 25 percent, the California Pool and Spa Association is promoting a campaign called Let's Pool Together and is lobbying water districts to quash proposed bans on filling pools and spas.

The industry cites an in-house study that found that a standard-sized pool, plus decking, uses one-third the amount of water as an irrigated lawn after an initial fill.

"We're not saying, 'Solve the drought, put in a pool,' but the bottom line is people who put in a pool are making a decision to do something more water efficient with their backyard. They're saving water," said John Norwood, the California Pool and Spa Association's president. "Pools are landscaping."

Some water conservation experts question the pool industry's math and say, at best, residential pools and lawns use roughly the same amount of water after an initial fill. There are 1.18 million residential pools in California, according to Metrostudy, which tracks housing information.

And at least a dozen cities and water districts in the hardest-hit areas of the state have passed bans on new swimming pool permits, filling new swimming pools and draining and refilling existing pools.

The South Coast Water District, in one of the poshest areas of Orange County, approved a ban on filling or refilling residential pools and the city of San Jose, which is trying to cut water use by 30 percent, did the same in April. That city also prohibits topping off existing pools with more than one foot of water, although the mayor did remark that unfilled pools would make excellent skate parks. The bans generally do not include community pools.

"We're in a very significant drought. We're asking people not to water their lawns," said Kerrie Romanow, director of San Jose's environmental services department. "That does require some level of sacrifice."

Even as cities and agencies crack down, contractors in some parts of the state are seeing a small uptick in demand as the recession ends. Applications for new pool permits declined steeply during the recession, but pool contractors in some areas without pool-related water restrictions say business is up this spring.

The rebound is slower in California than other warm-weather states like Florida, Texas and the Carolinas that aren't experiencing intense drought, said Toby Morrison, Metrostudy's national sales manager.

"Our sales are up fairly significantly, but we have no idea how many people are influenced by reading in the newspaper and saying, 'Gee, I might not ever be able to fill it or will the neighbors throw rocks at me if I build one,'" said Cecil Fraser, owner of Swan Pools in Lake Forest, California.

Leigh McDonough is one California resident whose desire for a pool outweighed her concerns about the drought when she bought a new home.

She and her husband did some online research and discovered statistics that said their future backyard oasis would use the same amount of water as their lawn — and perhaps less if they used a pool cover and added some drought-tolerant landscaping, she said. Her water district has not yet implemented restrictions on swimming pool water and she filled the 21,000-gallon pool and hot tub last month using two garden hoses.

"For us, it was sort of a must-have when we bought this place," said McDonough, who hopes to replace her front lawn with artificial turf. "So, I'm happy that it's getting done now and that we were able to fill it."

Experts caution that the pool-versus-lawn calculations depend on too many variables to be reliable, including how much water splashes out, whether there's a pool cover to prevent evaporation and how often the lawn was watered before it was ripped out.

In the end, the water used for pools and lawns is roughly the same, said Peter Gleick, president of the Pacific Institute in Oakland, a non-profit research institute focused on the environment and sustainability. And letting a lawn die or replanting with desert landscaping uses dramatically less water than a pool, so the comparison misses the point, he said.

"These are luxuries and we're in a really bad drought and everybody needs to step up instead of pointing the finger at the other guy," Gleick said.

The pool industry is also trying to change the behavior of its clientele.

Most homeowners hate the ugly and cumbersome bubble covers that can slash a pool's evaporation rate by half so some pool contractors are offering sales to encourage their use and conducting studies to determine which types work best. Others are experimenting with invisible chemicals dropped into the pool water that reduce evaporation and pool designs with less surface area to minimize evaporation.

And "water neutral" pools, popularized in Australia during the epic drought there, are a hot topic here.

Those pools use rain water that's collected in reservoirs and then treated to refill the swimming pool. One contractor in drought-ravaged Walnut Creek, California, recently dug a reservoir next to a homeowner's new pool to make this kind of closed-loop system, said Fraser, the pool contractor.

"We're very visible and that's why we get the attention. We're like the pretty girl in the crowd," said Fraser. "But we're probably as good a steward of water as anybody around because it's in our best interest."