All of these factors add up to an estimated $5.4 billion in water improvement projects needed throughout the state.

"The thing you have to understand is demand for water is soaring. Supplies are limited and shrinking. Prices are rising," said state Rep. Guy Liebmann, R-Oklahoma City, former chairman of the Oklahoma City Water Utilities Trust.

"Yet few of us are investing in the resource that is the source of life itself," he said. "We wait until it's just a disaster before we start thinking about it."

Last year the Legislature voted to pay for a new Comprehensive Water Plan. Due in July 2011, the plan will address water needs, competing water interests, vulnerability to drought and flooding, environmental protection and economic development through 2016.

Balancing those concerns won't be easy. Population and water use are expected to keep growing.

The state Department of Commerce predicts that Oklahoma will add 17 percent more residents over the next 20 years, with a population of 4.2 million by 2030.

Water use will grow nearly as fast, at about 14 percent, according to the U.S. Army Corps of Engineers. The state will use more than 744 million gallons of water in the year 2030, the Corps of Engineers estimates.

The effects of growing demand and limited supplies were sped up during last year's deepening drought. In one instance, Lone Chimney Lake in northcentral Oklahoma ran out of potable water. That left the towns of Glencoe, Morrison, Yale, Blackburn, Skedee, Marimec, Terlton, Pawnee and Cleveland high and dry.

The drought may be over. But even long, soaking seasons cannot wash away the strains on a finite water supply. Steve Thompson, executive director of the state Department of Environmental Quality, said as much to the governor's annual water conference in November 2006, before the rains came last spring.

"If there is a sense in the room that a good, hard, general rain would solve all our problems, my job is to try to dissuade you from that notion," he said.

That reality is especially apparent in areas that draw water from wells.

Drought-breaking rains helped refill the state's 34 major reservoirs, most of which are now into their flood-control pools. These reservoirs store more than 4.2 trillion gallons of water.

But underground aquifers are still depleted.

These aquifers, whether bedrock or the more shallow alluvial areas near rivers and streams, will hold more than 24 times the amount of water pooled in the reservoirs. But pressure on their stores is growing.

The state reports a more than tenfold increase in the number of wells drilled into these aquifers since 1972. And several years with little rain in the past decade have dropped the water level in each.