PHOENIX — The credit crisis, which has made loans more difficult to obtain, has had a dramatic effect on the sale of pools around the country, putting companies out of business and leaving others scrambling to diversify.

Pool builders were feeling the pinch as home sales slowed during the past two years, but the unwillingness of lenders to approve credit has accelerated the decline.

"I cannot overstate the importance of financing to the pool industry," said Erika Taylor, editor of Pool & Spa News, an industry magazine. "You have customers with good credit, and they're completely ready to buy a pool. They're not behind on their home payments. They are employed, and they can't get a loan."

Some potential customers are holding off until they have a larger share of cash. Others are parting with their cash, or buying with credit cards. Several small builders have folded, leaving customers with unfinished pools. Some remaining builders are gaining customers from closed businesses.

Warm-weather states, including Arizona, Florida, Nevada, Texas and California, all report declines in pool construction.

For example, the number of permits issued in 2008 to build pools in Maricopa County, Ariz., could end up at roughly half the number issued in 2007, and at less than 30 percent of the number issued in 2005, according to data from Rider Permit Service, a data collector for the pool industry. Maricopa includes the city of Phoenix.

Late last month, Riviera Pools, a larger company in Phoenix, laid off nearly all of its employees and closed its corporate office and sales offices. On Oct. 2, the company filed for Chapter 11 bankruptcy protection.

Owner Ron Ostlund said he threw in the towel after months of dealing with lenders who continued to decline financial assistance to potential customers.

Typically, new-home buyers use financing options such as rolling the cost of building a pool into their mortgage. Buyers of pools also can finance construction by obtaining a second mortgage or a home-equity line of credit. The average cost to build a pool in Maricopa County is $30,000.

Some banks have the money to lend but now they have stricter requirements to get it, said Tanya Wheeless, president of Arizona Bankers Association in Phoenix.

"We've seen that second source for banks being able to borrow from other banks ... drying up," Wheeless said. "So banks can't lend any more money than they have, which means it goes beyond being an underwriting decision."

California Pools and Spas of Mesa, Ariz., is one business that is adjusting to the credit crunch.

Owner Jeremy Smith said his pool sales have dipped 40 percent in the past two years, forcing him to cut his workforce from 100 to 60 employees. To bolster his income, he now depends on remodeling older pools and building commercial pools. Recent projects include pools at hotels and apartment buildings.

Also, Smith has partnered with a local bank to create a pool-finance program. In addition, Smith is a dealer for Capital One, which offers lines of credit for home improvement. Still, he said, the criteria are strict, with high credit scores required.

With pool companies closing and uncertainty persisting about others, buyers worry they will be left with an unfinished pool.

That's what happened to Juanita Louder of Apache Junction, Ariz. In August, she bought a $30,000 pool from a company based in Phoenix. The company closed in September, leaving a big hole in her yard without telling her what was going on.

"Nobody returned my calls for days," she said.

Finally, an employee returned her call. Since then, she has filed a complaint with the Arizona Registrar of Contractors and with the Better Business Bureau.