SCOTTSDALE, Ariz. — The survival — or at least the basic sustenance — of hundreds in a desert community amid the horse ranches and golf courses outside Phoenix now rests on a 54-year-old man with a plastic bucket of quarters.

John Hornewer picked up a quarter and put it in the slot. The lone water hose at a remote public filling station sputtered to life and splashed 73 gallons into the steel tank of Hornewer’s water hauling truck. After two minutes, it stopped. Hornewer, one of two main suppliers responsible for delivering water to a community of more than 2,000 homes known as Rio Verde Foothills, fished out another quarter.

“It so shouldn’t be like this,” Hornewer said.

Some living here amid the cactus and creosote bushes see themselves as the first domino to fall as the Colorado River tips further into crisis. On Jan. 1, the city of Scottsdale, which gets the majority of its water from the Colorado River, cut off Rio Verde Foothills from the municipal water supply that it has relied on for decades. The result is a disorienting and frightening lack of certainty about how residents will find enough water as their tanks run down in coming weeks, with a bitter political feud impacting possible solutions.

The city’s decision — and the failure to find a dependable alternative — has forced water haulers like Hornewer to scour distant towns for any available gallons. About a quarter of the homes in Rio Verde Foothills, a checkerboard of one-acre lots linked by dirt roads in an unincorporated part of Maricopa County, rely on water from a municipal pipe hauled by trucks. Since the cutoff, their water prices have nearly tripled. The others have wells, though many of these have gone dry as the water table has fallen by hundreds of feet in some places after years of drought.

“This is a real hard slap in the face to everybody,” said Hornewer, who has been hauling water to his neighbors for more than two decades. “It’s not sustainable. We’re not going to make it through a summer like this.”

The prolonged drought and shrinking reservoirs have already led to unprecedented restrictions in usage of the Colorado River, and the federal government is now pressing seven states to cut 2 to 4 million acre feet more, up to 30 percent of the river’s annual average flow. The heavy rain and snow pummeling California have not had much impact on the Colorado River Basin and major reservoirs Lake Powell and Lake Mead have fallen to dangerous levels.

This grim forecast prompted Scottsdale to warn Rio Verde Foothills more than a year ago that their water supply would be cut off. City officials stressed their priority was to their own residents and cast Rio Verde Foothills as a boomtown of irresponsible development, fed by noisy water trucks rumbling over city streets. “The city cannot be responsible for the water needs of a separate community especially given its unlimited and unregulated growth,” the city manager’s office wrote in December.

Scottsdale Mayor David Ortega was unmoved when his Rio Verde Foothills neighbors cried foul.

“There is no Santa Claus,” he said in a statement last month. “The megadrought tells us all — water is not a compassion game.”

With growing urgency, Rio Verde Foothills residents have pursued two main alternatives to find a new source of water, although bitter disagreements over the best solution have divided the community and pitted neighbors against each other.

For the past several years, some residents have sought to form their own water district that would allow the community to buy water from elsewhere in the state and import what they need, more than 100 acre-feet of water per year. Another group prefers enlisting a Canadian private utility company, Epcor, to supply the community, as it does with neighboring areas. But political disputes have so far foiled both approaches.

The water district plan — which supporters say would give them long-term access to a reliable source of water — was rejected in August by the Maricopa County supervisors. The supervisor for the area, Thomas Galvin, said he opposed adding a new layer of government to a community that prizes its freedom, particularly one run by neighbors with the authority to condemn property to build infrastructure.

Galvin preferred Epcor, a utility that, if approved, would be regulated by the Arizona Corporation Commission.

The water district “would be subject to the whims of five local lay people serving on its board. Whereas Epcor cannot assess anything on these folks unless the corporation commission approves it,” Galvin said in an interview. “To me, it was just a sensible plan all around.”

Scottsdale officials didn’t see it that way. To avoid an interruption of service to Rio Verde Foothills, Epcor needed Scottsdale to agree to treat the water it would provide — but the city has not agreed to do so.

Mayor Ortega’s office said he was not available for an interview.

That has left Rio Verde Foothills without any clear path to solve their water problem. Some homeowners have sued to challenge the Maricopa County decision to block the water district. And a larger group of residents filed a lawsuit Thursday in Maricopa County Superior Court seeking an injunction against Scottsdale to force the city to reopen its taps.

“What Scottsdale has done is inhumane. Dangerous. They’ve left us without fire protection. They’ve left us without water for families,” said Christy Jackman, a resident who helped lead an effort to raise thousands of dollars to pay lawyers to seek the injunction. “Mostly what we have right now is palpable fear.”

Two days before the cut off, Stephen Coniaris, a retired emergency room physician, had his 5,000 gallon underground storage tank topped off. His solar-powered home overlooking the McDowell Mountains was already well-equipped to conserve through the worst drought in a millennium. He had a low-volume dishwasher; a toilet that consumed just 0.9 gallons per flush.

But this new dilemma has pushed Coniaris and his wife, Donna Rice, into more extreme territory. They joined a gym in Scottsdale to take showers. They haul dirty clothes to friends’ homes or a laundromat. Plastic buckets in the backyard collect the rainwater, however rare, that falls from spouts off the roof. This goes into 3.5 gallon plastic jugs stationed in the bathroom to flush the toilet — although they now usually make other arrangements.

“We pee outside,” Coniaris mentioned, as he ate his lunch of barbecued chicken off paper plates, to avoid doing dishes.

These measures have dropped the couple’s average water consumption from 200 gallons per day last year to 30 gallons per day in the first week of January, as they anxiously await a solution for their community. As the cutoff deadline approached last year, some neighbors sold their homes, and others have watched property values decline.

Rice said they are not planning to sell, but she couldn’t imagine much demand in any case.

“It would be crazy to buy our house at this point,” she said.

But staying will grow increasingly fraught the longer Rio Verde Foothills must rely on distant sources of hauled water.

Cody Reim, who works for a company that installs metal roofing, normally pays $380 a month for the roughly 10,000 gallons per month he consumes along with his wife and four young children. If his family continues to use water at the same pace, the new prices will put his next bill at $1,340 per month, he said, almost as much as his mortgage payment.

“That’s a life-changing amount of money for me,” he said.

Reim has called or emailed all of his state and federal representatives, with most ignoring his inquiries, he said, and visited the state legislature last month to try to speak with Arizona’s former governor. On Tuesday, he attended a protest at city hall in Scottsdale — the city where his children attend school, where his family does nearly all its shopping — to demand water for his community.

“I thought, this is the United States of America, we do so much in humanitarian aid to other countries that don’t have water, they’re not going to let taxpaying citizens of this county go without water,” he said.

“You don’t think this could happen,” he added. “You have this belief that there’s going to be help.”

‘You fill this whole thing up with water?’

The help, for now, is Hornewer, and the other water haulers who service Rio Verde Foothills.

Until this year, the six trucks in his family-run business, relied on the nearby Scottsdale filling station. It would take about 15 minutes, he said, to fill his 6,000 gallon tank, quickly punching a code into the automated system and receiving his torrent of water.

On Saturday, he spent an hour driving 45 miles to Apache Junction, one of the few towns in the vicinity with an available filling station, a small cinder block house with a single hose. It now takes 85 quarters — and nearly three hours — to fill up.

“I’ll do what I have to do for my people,” he said. “But wow, this is getting stupid.”

As Hornewer waited, other people with trailer-loaded personal water tanks drove up, impatiently eyeing his commercial hauler. One of those idling behind him, a man in a cowboy hat and a checked shirt, eventually got out of his pickup and sauntered over. He rapped his knuckles on Hornewer’s tank.

“You fill this whole thing up with water?” he asked. “Serious?”

The tedious process has reduced the number of possible water loads Hornewer’s company can make by 75 percent. Driving this far in a truck that consumes a gallon of diesel every 3.5 miles, has dramatically increased his costs. During hot summer months, when water usage spikes, the math on how he might satisfy the Rio Verde Foothills water demand simply does not add up, he said.

“We’ve got two months. And then we’re done,” he said. “In two months, it’s not going to matter how much money you have. In two months, it’s going to be: You’re going to get your allocation, your ration of water: use it wisely.”

Some of Hornewer’s customers require a large supply. The Miller Ranch, which attracts visitors from around the world to ride their collection of Missouri Fox Trotter horses, uses about 24,000 gallons a month to sustain some 40 horses and the people who visit and live on the 20-acre ranch.

“It’s certainly a problem,” said Sharon Yeagle, the ranch manager.

There is little alternative, however, if they want to keep their animals.

“It’s not like we can go buy bottled water for them,” she said.

Hornewer keeps a printout on his dashboard which shows how much water each customer has left. As their tanks decline, electronic monitors alert him so he can prioritize his deliveries. On Saturday, Britney Kellum was at the top of his list.

As he filled her underground tank, Kellum came out to thank him.

Kellum is a renter and her job in logistics for a trucking company gives her an appreciation for the new obstacles to find water. She also sympathizes with Hornewer, who has faced attacks on Rio Verde Foothills social media sites by residents angry about the higher prices and his support for the attempt to create a water district.

“It is getting very personal,” Kellum said.

“It’s unfortunate, I think, that it got to this point,” she added. “This could be make or break for us.”