Last week, Governor Jerry Brown ordered the state to reduce its potable urban water usage by 25 percent compared to 2013 before March of next year. Just how the order—California’s first statewide water-rationing mandate—might restrict West Marin’s access to public water sources remains unknown, and local water districts are still waiting to find out how exactly their operations will be affected.

The order banned a host of watering practices and offered a rebate for replacing inefficient household devices. It also required the state to replace 50 million square feet of public lawns with drought-tolerant plants, to limit water use on school campuses, cemeteries and golf courses and to ask local districts to submit monthly efficiency reports.

According to local officials, the governor’s order will be interpreted and codified later this month by the State Water Resources Control Board and the Department of Water Resources. The state will then hand down regulations to local water agencies that qualify as “urban,” meaning they service a minimum of 3,000 users. 

“It looks like [the order is] going to affect everybody [in our district],” said Chris DeGabriele, the general manager of the North Marin Water District. “Though it’s a little unclear exactly how far it will go at this point in time.”

The proclamation follows on the heels of the governor’s January and April 2014 calls for local agencies to voluntarily reduce water consumption in California by 20 percent based on 2013 figures. That voluntary measure has largely failed, officials say, though West Marin’s two urban-sized water districts have not yet voted on the measure (which the state adopted only last month). North Marin and its sister urban district, Marin Municipal Water District, provide potable water to the Point Reyes Station, Olema and Inverness Park areas and the San Geronimo Valley. According to their managers, both districts will move forward with resolutions this month to adopt the state’s voluntary 2014 measure, which includes a ban on the use of water to clean driveways and a two-day weekly maximum for residential landscape irrigation.

Both districts will await further instruction from the state before implementing any further measures. 

“We have to wait a little bit to see what the state board does with the governor’s executive order,” Mr. DeGabriele said. “But certainly there will be some mandatory requirement for reducing water use.”

Smaller West Marin water providers say they have already achieved or surpassed last year’s voluntary 20 percent water-reduction request. Both the Bolinas Community Public Utility District and the Stinson Beach County Water District reported to the Light that they have seen a 25 to 30 percent reduction in their towns’ water usage since 2013.

“We’re doing what we need to do anyway,” said Jennifer Blackman, the general manager of Bolinas, which draws its water from Arroyo Hondo Creek. “We’re doing this because of what is necessary [in Bolinas].”

The Inverness Public Utility District reported a comparatively lower tally, a 18.5 percent reduction, though the district’s manager, Scott McMorrow, is confident that conservation will drop further in the wake of the new order.

“The people in Inverness are water-smart,” he said. “We’ll see water reduction based on [media] headlines.”

Managers in Bolinas and Stinson Beach—which is sourced from creeks and groundwater at multiple sites—have pledged to continue water-conservation outreach efforts through newsletters and public notices. Still, Ms. Blackman worries that winter storms arrived early in West Marin this year, mostly in December, and have since not returned as often as they have in springtime months of past years.

“With that distribution of rain, we’re definitely concerned this year,” Ms. Blackman said. “We may have to move to mandatory rationing, but it’s too early to say yet.”

Mr. McMorrow echoed the opinion. Inverness, like Bolinas, depends on around 28 to 29 total inches of rainfall each winter to have enough reserves to comfortably support residents through summer and fall. (Inverness’ water flows from springs originating on the Inverness Ridge that feed into the First, Second and Third Valley Creeks.) Inverness has recorded slightly over 27 inches of rain so far this year.

“We’re in the comfort zone,” Mr. McMorrow said. “But we’d obviously like to see more.”

Meanwhile, as West Marin’s water districts await instructions, the governor has spared the state’s biggest water consumer: agriculture. In lieu of mandatory usage reductions, Gov. Brown is requiring that only agricultural water agencies with customers who operate on more than 25,000 acres of land draft annual drought management plans to monitor water efficiency.

Even so, the president of the Marin County Farm Bureau, Sam Dolcini, predicts that dairy and beef ranchers in West Marin will continue to be hit hard by the state’s longstanding drought. Fewer days are available for ranchers to graze their cattle, he said, and farmers are devoting their water supplies to cash crops—like onions—at the expense of alfalfa, the most desired cattle feed. As a result, beef ranchers are forced to wean calves months earlier than usual, resulting in cattle that weigh 200 to 300 pounds less and fetch lower prices.

“It is by far the worst conditions that almost anyone can remember,” Mr. Dolcini said. “We’re starting to wonder what normal is anymore, actually.”