Opponents say it could add to the already high cost of housing and stymie development.

Proponents say the fee would offset new development's water use by generating money to for water conservation equipment such as low-flow shower heads and toilets, or by finding and buying "new" supplies, such as water recycling and seawater desalination.

"You could replace 5,000 toilets in existing developments," said Keith Lewinger, the Fallbrook Public Utility District official who proposed the idea at the San Diego County Water Authority's December meeting. "It (the fee) really primes the conservation pump."

But other water officials who oppose the idea said developers already pay expensive water meter fees to tap into existing water supplies.

They say a new fee would jack up housing prices, could create a de facto moratorium on home-building, and represented a knee-jerk reaction to the state's current water-supply worries.

Southern Californians are facing a possible 30 percent cut to their State Water Project supplies from Northern California in 2008 because of a court ruling to protect fish in the Sacramento-San Joaquin Delta. The region relies mainly on water imported from Northern California and the Colorado River - finite supplies that are not growing larger like the state's population.

Water officials statewide have called for people to voluntarily cut their water use to stretch supplies next year. Meanwhile, many San Diego County farmers and growers - including those in Fallbrook - have already been handed mandatory 30 percent water cuts.

Those actions have rankled some residents. They argue that if there were "real" water shortages, developers should be forced to stop building new homes.

Lewinger said those arguments prompted his proposal, which is expected to spark vigorous debate.

At the Water Authority's Dec. 6 board meeting, its Water Planning Committee, which includes Lewinger, voted to direct the agency's staff to talk with water agency general managers countywide, and return with possible "offset fee" proposals next year.

"I imagine this will take a minimum of six months to even come up with a straw man, a proposal," Lewinger said recently. "It (the proposal) just seemed like the right thing to do at the right time."

Two of the Water Authority board members who voted against talking about the fee idea were Mark Watton, general manager of Chula Vista's Otay Water District, and Jim Barrett, director of the city of San Diego's water department.

Both Watton and Barrett said a new fee would just mean more money for home buyers and home builders to pay.

"If you build a new house, when you go to the Otay Water District, you're already paying about $10,000 for a new (water) meter," Watton said.

Watton said water agencies needed to get people who already have homes to use water more wisely.

"Do existing homeowners need to be putting 80 inches of water onto their lawns each year?" he said. "That's more than the Amazon."

Barrett said Lewinger's fee idea could be the same as putting a moratorium on all new building. He said that was because the fee would force developers - who are in the business of building homes and not finding water supplies - to try to find "new" water to supplement Colorado River and delta supplies. Barrett suggested that water agencies such as the Water Authority were having trouble finding "new" water.

"If (new) water was real and obtainable, wouldn't we all be pursuing it now?" Barrett asked at the December meeting.

Barrett also said last week that the state's current water-supply problems could be a short-term situation, and did not warrant creating a long-term fee to tack on to development.

Barrett said state water officials and politicians could ultimately craft new pipeline and dam projects to address the delta's environmental problems.

But Lewinger said that even if the delta's problems disappeared, Southern California's key imported water supplies were not going to get bigger - meaning new development could stretch existing supplies to the breaking point.

Watton suggested that Lewinger was being overly sensitive to the complaints from growers in rural Fallbrook who have had to take 30 percent cuts. Watton, and others, said those growers and farmers voluntarily signed contracts to swallow the first water cuts in hard times in exchange for discounted water rates.

"I'm very sympathetic to the growers," Watton said, "but what gets lost in the story is that they made a business decision all those years ago to take discounted rates."

Others think Lewinger's fee proposal is a good one.

One of those was Water Authority Board Member Gary Arant, the longtime general manager of the Valley Center Municipal Water District - which also has many agricultural customers facing mandatory water cuts.

"I think it's an idea worth exploring," he said. "When you are facing a question about water supply, and asking existing customers to reduce usage, the question that keeps coming back to you is, 'How can you continue to allow new development to take place?' "