ROHNERT PARK AND COTATI, CA — Some of the driest months on record in California have set residents up for potential water restrictions this summer.

Yuba City became one of the first communities in Northern California to impose mandatory water restrictions amid "severe shortage." Residents there will have to limit landscape watering to Mondays and Thursdays, only use hoses with a shut-off nozzle and turn off non-recirculating fountains, the city said in a news release.

"This is a direct response to the current water supply shortage occurring with the ongoing drought and the recent issuance of a state executive order calling for 20 percent water conservation compared to 2020 usage," city officials wrote in a release.

In Petaluma, residents are restricted to watering two days a week — overnight on Saturday and Tuesday, between 8 p.m. and 7 a.m. — under Stage 4 of the city's Multi-Stage Water Shortage Contingency Plan.

While such restrictions have not yet reached Rohnert Park and Cotati, a worsening drought situation in Sonoma County and throughout California could prompt officials to impose new rules.

In Rohnert Park, the city is currently under Stage 1 of its Water Shortage Contingency Plan which requires customers to reduce water use by 20 percent. The following mandatory water-conservation measures were in effect as of Monday in Rohnert Park:

In Cotati, the City Council adopted a Stage 2, voluntary community-wide water conservation target on May 25, 2021, which remains in effect. Cotati water customers are asked voluntarily contribute to a 20-percent reduction in water use. Further, water waste from leaks, breaks or overspray from irrigation, is prohibited.

"Based on very low amounts of rainfall this year, we are looking at another very dry year and continuing drought conditions," Cotati City Manager Damien O'Bid said in his April 26 update. "Customers are asked to continue to conserve water again this year. We encourage everyone to sign up for our free or low-cost conservation programs and leak alerts."

Meanwhile, six million residents in Southern California will fall under new water restrictions June 1. Outdoor watering in dozens of Southland cities will be restricted to just one day a week, according to the Metropolitan Water District, which serves 18 million people.

"This is a crisis unlike anything that we've seen before," MWD Executive Officer Deven Upadhyay said.

Although water conservation in all facets of daily life will help, officials have identified outdoor watering as one of the biggest contributing factors of the water shortage. As a result of water conservation efforts, yellow and brown lawns will be the norm this summer.

Residents across California were urged to make changes to save water such as removing lawns and replacing them with native plants that require less irrigation.

During the state's annual April 1 Sierra Nevada snowpack survey, officials found that levels were just 38 percent of average. The state has received 15.63 inches of rain this year, 75 percent of the historical average, according to California Water Watch.

This, coupled with Gov. Gavin Newsom's January emergency drought declaration, could eventually trigger another summer of water restrictions statewide.

Despite the healthy dosage of snow and rain to Northern California last month, the state is still sinking into drought.

The state emergency regulations direct residents to:

To save water inside the home, residents can fix leaky pipes, buy a low-flow showerhead, install a low flush toilet, upgrade old dishwashers and install a water aerator onto the kitchen sink.

Newsom last month directed water suppliers statewide to ramp up conservation efforts by advancing water-shortage contingency plans.

State lawmakers recently took a 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 per person per day. The rule doesn't directly apply to customers, meaning regulators don't cite individuals for using more water than permitted. 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.

Most of Northern California and 92 percent of the state is facing severe drought conditions, according to the National Integrated Drought System. Such conditions have the potential to lengthen and intensify fire season as fuels continue to dry out. Severe drought can also stress trees, trigger plants to increase reproductive mechanisms and increase diseases among wildlife.

Much of the central part of Northern California is under extreme drought. Under extreme conditions, livestock often need costly supplemental feed as little pasture remains, fire season can last year-round and water is inadequate for agriculture. Reservoirs in these areas are also extremely low.

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.

The Associated Press contributed to this report.