Even with the vast Atlantic Ocean lapping at its shores and more yearly rainfall than most of the country, South Florida once again finds itself wanting for water.

South Florida typically gets 52 inches of rain a year -- 14 inches more than soggy Seattle -- but doesn't have the storage capacity to capture enough water to quench the thirst of a growing population.

"It's a storage issue, that's the problem," said Bevin Beaudet, water utilities director for Palm Beach County. "There are solutions, but they are not cheap, and they are going to take a while."

Much of the rain is flushed out to sea in canals built decades ago to drain the Everglades to make room for sugar cane fields and suburbia.

Instead of collecting rainwater, most communities continue to tap shallow underground water supplies and rely on water from Lake Okeechobee and the Everglades for backup.

During the current drought, the demands of almost 6 million people strain this cheap and easy approach, and leave them waiting for summer's drenching rains.

With water levels in the Everglades dropping more than expected last week, South Florida could feel its watering restrictions tighten further as early as Monday. Low water levels in Lake Okeechobee triggered three-day-a-week watering restrictions last month.

These developments make it even more urgent for cities and counties to develop alternative sources of water. That mandate was issued by the South Florida Water Management District earlier this year when it limited the Everglades as an additional water supply.

Most of the almost 1 billion gallons of drinking water produced by local utilities each day in South Florida comes from an underground source called the Biscayne aquifer. Wells 100- to 150-feet deep produce water that requires minimal treatment.

"It is easy to get to and inexpensive to treat," said Chip Merriam, deputy executive director for the South Florida Water Management District.

Rainwater that soaks into the ground replenishes the Biscayne aquifer, but pavement covers much of the ground that used to absorb water, and drainage systems make it hard for the aquifer to get as much rainwater as it used to.

Water from conservation areas along the eastern Everglades also flows through canals to replenish community well fields, areas where water seeps into the ground and eventually the aquifer. Water managers limit how much water communities can take to conserve water for natural areas.

Lake Okeechobee, fed by the Kissimmee River to the north, provides backup water that communities count on to resupply canals that recharge their well fields.

While water managers pressure cities to find alternative water supplies, they search for ways to better control the level of Lake Okeechobee.

Lake Okeechobee's average water level was 10.48 feet on Friday, 4 feet below normal. The historic low of 8.97 feet was reached during the 2001 drought.

Part of the reason the lake dipped was that water managers last year lowered levels in anticipation of hurricanes that never materialized. Forecasts for a busy storm season and concern about the strength of the lake's 70-year-old dike prompted managers to release lake water to the Caloosahatchee and St. Lucie rivers.

The water management district, which manages the lake with the Army Corps of Engineers, is working with Columbia University to analyze long-term climate variations to avoid lowering the lake for storms that never show up, said Upmanu Lall, chairman of Columbia University's Department of Earth and Environmental Engineering.

In 2006, South Florida's annual average rainfall was 40.75 inches, instead of the normal 52 inches. So far this year, rainfall totals are 4 inches below normal.

Each year, South Florida drains an average of 3 million acre feet of rainwater out to sea, compared to the 1 million acre feet that used to flow off the land naturally, said John Mulliken, director of water supply planning for the district. One acre foot equals about 326,000 gallons of water.

Reservoirs planned to restore the natural flow of water to the Everglades would help capture more rainwater.

"Everybody would win," Merriam said.

Environmental groups contend the state needs more reservoirs before allowing more development.

"The natural system cannot continue to support the amount of people coming here," said Lisa Interlandi, an attorney with of the Everglades Law Center.

Rising land prices and the difficulty of building reservoirs in flat South Florida create significant hurdles, Merriam said.

A reservoir could supplement drinking water supplies in Palm Beach and Broward counties, if community leaders can work out a deal to share.

An old rock mine west of Royal Palm Beach was turned into the L-8 Reservoir to store rain water to replenish the Loxahatchee River, which runs through northern Palm Beach County.

A new plan calls for sending some of the water south. Palm Beach County commissioners have questioned sending water elsewhere when they have a growing population to serve, but the communities involved agreed to at least study the possibility.

Broward County doesn't have much land on which to build reservoirs, said John Crouse, director of Broward County's water management division.

"Everything is being looked at," he said.

Anticipating 1.74 million new residents in Florida's lower east coast by 2025, water managers project a need for an additional 393 million gallons of water a day.

Alternative water supplies being considered include recycling treated wastewater for irrigation and to supplement water supplies. Utilities also can tap into the Floridan aquifer, a source 1,000 feet below the ground and beneath the Biscayne aquifer, that produces salty water requiring more costly filtration. The price tag for these and other projects totals $2.63 billion.

Converting ocean water to drinking water seems like an obvious alternative, and Broward County and other water providers are considering it. However, the cost of building a high-tech desalinization plant would be steep, and there are environmental repercussions to disposing of the leftover salty discharge.

"There are issues with everything we try to do," Crouse said.

Local leaders need to show the "political will" to limit development and commit to building more reservoirs, said Susan Kennedy, president of the Loxahatchee River Coalition.

"The problem is we throw all our water away," Kennedy said. "We continue to develop land and plant that final crop of asphalt and concrete."