SACRAMENTO — California’s top water guzzlers — the people who use tens of thousands of gallons more than their neighbors to keep lawns bright green during serious droughts — could soon be hit with higher water bills and their names made public if the drought continues.

A law signed late Monday by Gov. Jerry Brown requires retail urban water suppliers with more than 3,000 customers to put in place rules that define “excessive water use” and impose them during drought emergencies.

The cities, water districts and private water companies have two choices:

They can impose tiered rates that charge a higher amount to people who use more than a certain target, as San Jose Water Co. and some other providers are already doing this year. Or they can put in place a fine for households using more than a set amount, which then triggers a requirement in state law mandating that their names be made public.

“Households that guzzle water — while their neighbors and most other Californians abide by mandatory reductions — will no longer be able to hide and persist in their excess,” said state Sen. Jerry Hill, D-San Mateo, who wrote the measure.

Hill said he pushed the bill, SB 814, after reading about a few individual customers who blatantly disregarded calls for conservation during the current drought, such as one Beverly Hills homeowner who used 12 million gallons of water last year. Some water agencies charge the same amount per unit of water no matter how much water a customer uses, which allows wealthy homeowners to simply write a check and continue the practice.

The bill was supported by environmental groups such as the Sierra Club, along with the East Bay Municipal Utility District.

The district, which serves 1.4 million people in Alameda and Contra Costa counties, last year passed an “excessive water use ordinance” that penalized households using 984 gallons of water or more per day, which is four times the district’s average household use of 246 gallons per day.

The ordinance charged a penalty of $2 per water unit (each unit is 748 gallons) for all use above 984 gallons a day. Although that amount didn’t result in sky-high bills for the district’s most heavy water users, it did trigger a requirement in the state Public Records Act that the names of water customers who are fined for excessive use be made public.

Normally, water bills are not public record.

A number of celebrities and business leaders — including Oakland A’s executive Billy Beane, of Danville; Motley Crue lead singer Vince Neil, of Lafayette; and Chevron vice president George Kirkland, of Danville — all turned up on the list of water wasters.

“For us, it wasn’t perfect, but it did get people’s attention and provided more opportunities for conservation,” said East Bay MUD spokeswoman Andrea Pook.

“Most of them were never on the list again,” she said. “We don’t have any hard data about how much of it was public shaming, and how much of it was financial. People are motivated by different things.”

After winter rains boosted supplies, East Bay MUD dropped the excessive use ordinance for this summer.

The new law will be required anytime California is in a drought emergency as declared by the governor, and when a water agency is subject to mandatory conservation from the state or from its own water management plan. California remains in a drought emergency that Brown declared in January 2014.

And from June 2015 to May of this year, the state imposed mandatory water conservation targets on cities and water districts, with potential fines for agencies that failed to meet them.

Brown’s State Water Resources Control Board lifted those rules in June, however, allowing local agencies to set their own targets because winter rains improved the water picture in some parts of California. But Brown administration officials have said they could bring back the mandatory targets starting in January if statewide conservation levels fall and rains don’t materialize this upcoming winter.

That would kick in the rules required under Hill’s measure.

The bill was opposed by the Association of California Water Agencies, which argued that because drought conditions have eased enough for Brown to drop mandatory water conservation targets that he had previously imposed on cities statewide, the bill “would institute an unnecessary mandate.”

In a letter, the association called the bill “a top down statewide approach,” arguing that “local control is the most effective path to mitigating the effects of drought.”

One complicating factor: If a local water agency chooses to use tiered rates, rather than a penalty with public disclosure, to punish excessive water users, it could run afoul of a recent court decision. Last year, a state appeals court ruled that tiered water rates are unconstitutional if they charge more for water than a water agency spends to provide the service.

That didn’t invalidate tiered rates, but it required water agencies to begin documenting much more specifically how they arrived at those rates — spending more to drill a new well or buy water from out of the area, for example, to justify the higher tiers.

But Hill says there’s only so much water — and water used on lawns in excess means less to fight fires with or use in hospitals and other important needs.

“Water is a limited resource,” he said. “We have to take droughts seriously. All of us. Just because you can afford your way out of it, that’s not right.”

Paul Rogers covers resources and environmental issues. Contact him at 408-920-5045. Follow him at Twitter.com/PaulRogersSJMN.