Californians face higher water prices and permanent conservation measures amid drought, global warming and population growth in a state that has long struggled to satisfy urban and agricultural needs, the administration of Governor Jerry Brown said Thursday.

It will take up to $500 billion to improve the state's water infrastructure to improve supplies, reduce flood risk and shore up the fragile ecosystems that provide water for people, farms and wildlife, the state's top natural resources officials said in a long-awaited update to California's water plan.

"Water is going to cost more for Californians in the future," said Mark Cowin, director of the state department of water resources, in a conference call with reporters on Thursday. "That's a reality we're all going to have to get used to."

California is in its third year of a catastrophic drought that has dried up wells and forced farmers to leave fields fallow.

But the state has long struggled to meet the water needs of thirsty cities and its mammoth agricultural sector, prompting a century of political fights between the wetter north and the drier south.

A proposal to spend $7.5 billion on reservoirs, underground storage and other water-related infrastructure was caught in partisan bickering for nearly a year before lawmakers agreed to put it on next week's election ballot. Republicans argue for more funding for reservoirs while Democrats say damming rivers and flooding canyons would damage the environment.

The state first developed a plan to manage limited water resources in 1957, updating it roughly every five years since then. The latest version focuses on ways to build and pay for improvements to the state's sagging infrastructure, including dams and reservoirs, as well as investments in new technology such as desalination plants and wastewater recycling.

The plan also makes conservation a priority, reinforcing a 2009 plan to reduce statewide per capita water consumption by 20 percent by 2020. It calls for spending on public awareness campaigns, research into water-use efficiency and alternative water supplies, and improved irrigation techniques.

"When the first plan was done in 1957, we had less than half the people in California than we have now," said Secretary of Natural Resources John Laird. "We did not have the impacts of climate change that we do now, and we did not have the pressure to make water conservation a way of life."