California's three-year drought could end up being the area's worst in 500 years, forcing even tougher restrictions on residents who have been cutting back on showers and farming already.On Friday, the State Water Project, which is the main distribution system of municipal water in California, announced it would not be allocating any water from its reservoirs to local agencies this spring. It is the first time it has taken such action in its 54-year history.Drinking water for 25 million people and irrigation for 1 million acres of farmland will be affected, Fox News reports. “We are on track for having the worst drought in 500 years,” B. Lynn Ingram, a professor of earth and planetary sciences at the University of California, Berkeley, told The New York Times.Gov. Jerry Brown already had called on Californians to cut back on water use by 20 percent.The State Water Project typically makes an announcement of water allocation on February 1, enabling farmers to plan what and how much they will plant based on how much water they will be able to use for irrigation. With the announcement that no allocation will be made, some farmers have opted to plant nothing, The New York Times reports. Others are planning to drill more wells to tap aquifers, which aren't regulated by the state. But previous years' use of those aquifers already have lowered their levels, and the ongoing drought has not given them time to return to normal range.With fears that California could be in a 500-year drought, officials want water supplies to be preserved in case they are needed over the next several years."These actions will protect us all in the long run," State Department of Water Resources Director Mark Cowin said in a news conference.The crisis is pitting farmers, city dwellers and environmentalists against each other, but officials are appealing to residents to put aside long-held divisions.A snow survey Thursday in the Sierra Nevada showed a snowpack of only 12 percent of normal, Fox reported. Reservoirs are lower than in 1977, one of the state's previous worst drought years.With forecasts still calling for no rain, 17 rural communities that provide water to 40,000 people could run out of within 60 to 120 days, The New York Times reports."Every day this drought goes on we are going to have to tighten the screws on what people are doing," the governor said."I have experienced a really long career in this area, and my worry meter has never been this high," Tim Quinn, executive director of the Association of California Water Agencies, told The New York Times. "We are talking historical drought conditions, no supplies of water in many parts of the state. My industry’s job is to try to make sure that these kind of things never happen. And they are happening."Besides drinking supplies and farm irrigation, the lack of water is threatening the endangered salmon and other fish species. And air pollution in Los Angeles, which had been declining over the past 10 years, is on the rise without rain to clean the air. Bans have been put on fireplace wood burning to combat the problem.