PHOENIX » There is one car for every 600 residents in this sprawling city, roughly 300 carwashing businesses listed in the yellow pages and benefit carwashes seemingly every weekend, fit for various purposes and needs.

There are carwashes to raise money for funerals and births, carwashes for struggling churches and cheerleading squads, carwashes for the children of murder victims and for sick children, too. One carwash helped advocates walk across Arizona in August in defense of gay rights. Another, organized by a neighborhood running group known as "Yummy Mommies," helped one of their members pay for a trip to the New York City Marathon next month.

Hoses hiss; water splashes over hoods, roofs and trunks; sponges make squishy sounds as they travel in circles, scrubbing layers of desert dust off plastic, rubber and metal. "Carwash, carwash" is the volunteers’ enticing call to passing drivers.

Chase Reynolds responded. He was on his way to brunch Saturday when he spotted the North High School cheerleaders at the gas station on the southeast corner of Seventh Street and Thomas Road, offering carwashes for whatever price anyone thought they were worth.

"Lift off the windshield wipers," Molly Kirkpatrick, an English teacher at the school and the coach of its varsity cheerleading squad, instructed Vicky Luna, 14. Vicky, a freshman, still trembles when she is standing on her teammates’ shoulders, way up in the pyramid that starts several of their routines. It is how they propped her up so she could wash the roof of Reynolds’ Chrysler PT Cruiser.

"I really needed a carwash," said Reynolds, 28, dropping $7 in a donations jar, the price of a "full-service carwash" — interior vacuum, soft-cloth wash, hand-towel dry — at a professional carwashing place eight blocks to the east.

Benefit carwashes are a venture likely to garner big returns. Costs are low: Materials amount to buckets, sponges and soap. Need is great: The desert dust that flies imperceptibly in the air here sticks to cars like glue sticks to paper. Demand is constant: Keeping a tidy car is like a ritualistic endeavor here, where distances are large, public transportation is lacking and cars are a necessity.

Competition from professional carwashing businesses is stiff. But benefit carwashing crews have at least one clear advantage: The money they earn is theirs alone and earmarked to a specific cause.

For the cheerleaders at North High School, where about 70 percent of the students are Hispanic and about as many qualify for free or reduced-price lunch, the money is to buy 800 balloons, as well as glitter, streamers, paper and paint for dozens of posters to be made and spread throughout the campus in advance of its homecoming festivities next week. The money also buys food for the students who help in the preparations, Kirkpatrick said.

For congregants at St. Stephens the Church of the Blessed, who are mostly black and "mostly struggling," as one of them, Troy Hardwick, put it, it is mostly, at this point, "to pay the bills" at the church.

For Julio Camacho, who works at a dairy plant in the city’s outskirts, it is to bury two of his sisters and two of his nephews, who died together in a highway car crash on Sept. 29.

"We went from funeral home to funeral home, and to bury one person here in Phoenix is around $10,000," Camacho said as he stood at the corner of Baseline Road and Seventh Avenue on Saturday, holding a blue sign bearing the words "carwash" and "RIP" over pictures of his relatives — Margarita Camacho, 43; Sandra Camacho, 35; Rigoberto Quintana, 12; and Angel Gabriel Romero, 2.

The family is going to send all but Angel’s body to Mexico, where its roots are and where burying the dead is cheaper.

"You don’t pay for the grave there, just tip the grave diggers," said Camacho, 24.

The first carwash, on Friday, at another spot along Baseline Road, brought in close to $2,000; cars lined up at dusk for a preweekend cleaning, he said. Saturday’s had not been as busy by midday, but he figured people would come by later or maybe drop by on Sunday, when the carwash would feature a display of lowriders and a DJ.

Kirkpatrick, of North High School, said the cheerleaders were hosting their second carwash ahead of homecoming, and that they raise anywhere from $300 to $400 on each of the carwashes they hold.

"For us, these are just a quick and easy way to make money," she continued.

Hardwick, of St. Stephens church, said congregants held carwashes "as much as people will let us." (They were using space at the parking lot of an auto-parts store, which, like many of the other businesses where benefit carwashes take place, lets the volunteers use its water for free.)

There are people who come by to get their cars washed because they stumbled upon a benefit carwash; people like Patrick Donovan, a Vietnam War veteran who said he goes around looking for a benefit carwash whenever he feels like cleaning his pickup truck; and people like S.B. James Sr. who come by not to get a wash, but just to help.

"We’ve all got to stick together," James, who owns a barbecue catering business, said after handing Camacho a $10 bill.

© 2012 The New York Times Company