ARVIN, California — Californians who grumble about not being able to water their lawns every day during the fourth year of a historic drought should swing by this small town in southern Kern County.

Drought or no drought, residents of this rural community can’t drink water from the tap and can’t even use it for cooking because high levels of arsenic — known to cause cancer — become even more concentrated when water is boiled.

“They worry about little things,” said Salvador Partida, president of the Committee for a Better Arvin, of the rest of the state. “We’re worried about not being able to drink the water.”

Last week Gov. Jerry Brown ordered the State Water Resources Control Board to enact mandatory cuts in water use by 25 percent. But more than 1 million California residents who live in mostly rural areas have unreliable access to safe drinking water, according to the Community Water Center, a non-profit group that advocates affordable and clean water for all Californians. For them, the ongoing drought that is ravaging the state's water supply is merely a sideshow.

Tap water that comes mostly from wells in these communities violated maximum contaminant level standards set by the Environmental Protection Agency at least once in 2012 – the most recent annual compliance report by the state’s drinking water program.

The number of violations with potential direct public health impact may affect even more people because of insufficient regulation and under-reporting, especially in areas served by small systems, said Heather Lukacs, project director at the Community Water Center.

More than 100 areas with fewer than 10,000 people had arsenic violations. Most are small, poor communities with a predominantly Hispanic population, some of whom are forced to spend up to 10 percent of household income on bottled water.

As of February of this year, the state reports that approximately 255,000 people served by 341 systems got water that was not potable. Almost half of the residents affected were getting water that exceeded the acceptable level of arsenic. The number is expected to rise over the entire year as more violations are reported.

“A lot of it is aged infrastructure,” said Sarah Buck, rural development specialist with the Rural Community Assistance Corporation. “And it’s very expensive to drill additional wells.”

There is now a statewide effort to bring safe drinking water to all Californians. The Agua4All campaign, a coalition of state and advocacy groups, including The California Endowment, has just launched pilot programs here and in nearby Lamont and the Coachella Valley to bring water fountains and water bottle filling stations to schools, parks and community centers.

The plan is to place Agua4All stations in all parts of the state that need them.

In 2012, the groups — all members of the Safe Water Alliance — sponsored The Human Right to Water Bill, which was signed into law by Gov. Jerry Brown. California became the first state to legally recognize that every human being has the right to safe, clean, affordable and accessible water adequate for human consumption, cooking and sanitary purposes.

The bill helped launch the current effort to provide “point-of-use water treatment systems” that remove arsenic from the water at drinking fountains in poor communities. A state grant of more than $400,000 is helping provide up to 69 filters to install on new Agua4All water fountains and continued maintenance. This is the first time the State Water Board has funded such a large number of treatment systems at water stations.

“Everybody knows the water can’t be drunk because it stinks,” Partida said. “I’m not going to drink that and I’m certainly not going to let my kids drink that.”

Partida and his wife spend $4 to $5 a week for two 5-gallon jugs of clean water.

“So you can imagine if you’ve got a lot of kids,” he said. “Ninety-nine percent of the population in Arvin buys bottled water … I’m amazed nobody was doing anything about it until now. A lot of people need to wake up.”