Southern California’s gigantic water supplier took the unprecedented step Tuesday of requiring about 6 million people to cut their outdoor watering to one day a week as drought continues to plague the state.

The board of the Metropolitan Water District of Southern California declared a water shortage emergency and required the cities and water agencies it supplies to implement the cutback on June 1 and enforce it or face hefty fines.

“We don’t have enough water supplies right now to meet normal demand. The water is not there,” Metropolitan Water District spokesperson Rebecca Kimitch said. “This is unprecedented territory. We’ve never done anything like this before.”

The Metropolitan Water District uses water from the Colorado River and the State Water Project to supply 26 public water agencies, which provide it to 19 million people, or 40% of the state’s population.

But record dry conditions have strained the system, lowering reservoir levels, and the State Water Project, which gets its water from the Sacramento-San Joaquin River Delta, has estimated it will only be able to deliver about 5% of its usual allocation this year.

January, February and March of this year were the driest three months in recorded state history in terms of rainfall and snowfall, Kimitch said.

The Metropolitan Water District said that the 2020 and 2021 water years had the least rainfall on record for two consecutive years. In addition, Lake Oroville, the State Water Project’s main reservoir, reached its lowest point last year since being filled in the 1970s.

California Gov. Gavin Newsom has asked people to voluntarily reduce their water consumption by 15%, but so far residents have been slow to meet that goal.

Several water districts have instituted water conservation measures. On Tuesday, the board of the East Bay Municipal Utility District voted to reduce water usage by 10% and cap daily usage for some 1.4 million customers in Contra Costa and Alameda counties, including Oakland and Berkeley. Households will be allowed to use 1,646 gallons per day — far above the average household usage of about 200 gallons daily — and the agency expected that only 1% to 2% of customers will exceed the limit, the San Francisco Chronicle reported.

The Metropolitan Water District restrictions apply to areas of Los Angeles, Ventura and San Bernardino counties that rely mostly on state water supplied through the district, including some parts of Los Angeles city. Mainly urban areas are impacted.

The MWD’s client water agencies must implement either the one-day-a-week outdoor use restriction or find other ways of making equivalent reductions in water demand, Kimitch said.

Although the water agencies support the water conservation move, it remains to be seen whether the public will do it, Kimitch said.

The Metropolitan Water District will monitor water use and if the restrictions don’t work, it could order an all-out ban on outdoor watering as soon as September, she said.

Meanwhile, state lawmakers have taken the first step toward lowering the standard for how much water people use in their homes.

California’s current standard for residential indoor water use is 55 gallons (208 liters) per person per day. The rule doesn’t apply to customers, meaning regulators don’t write tickets to people for using more water than they are allowed. Instead, the state requires water agencies to meet that standard across all of its customers.

But the state Senate overwhelmingly voted last week to lower the standard to 47 gallons per person per day starting in 2025 and 42 gallons per person per day beginning in 2030.

The bill has not yet passed the Assembly, meaning it is still likely months away from becoming law.

The U.S. West is in the middle of a severe drought just a few years after record rain and snowfall filled reservoirs to capacity. Scientists say this boom-and-bust cycle is driven by climate change that will be marked by longer, more severe droughts. A study from earlier this year found the U.S. West was in the middle of a megadrought that is now the driest in at least 1,200 years.