Tens of thousands of swimming pools across the Golden State are now plagued with stagnant water.

A byproduct of the prolonged housing slump and months of foreclosures, these mostly abandoned vessels are sprouting up daily in the once-booming suburbs of Los Angeles, Sacramento and San Diego.

Problem is, without proper maintenance these pools can quickly become algae and bacteria-infested eyesores, as well as breeding grounds for mosquitoes that carry West Nile virus and other diseases.

So who’s left to clean up the mess?

Enter the pool man. Or, more specifically, Paul The Pool Guy.

“There are a lot of houses out there in pretty bad condition,” says Paul Sibilla, owner of the Murrieta, Calif.-based service company that bears his moniker. “So yes, I’ve done a number of these jobs. And in this economy, it helps my business — a lot.”

Consider the stats: Nearly 180,000 California homes were in foreclosure by the end of 2008. In Los Angeles County alone, quarterly foreclosures jumped some 25 percent compared to the previous year. And in November, California led the nation in statewide foreclosures.

But a number of service technicians see opportunity, and several are cashing in on the glut of pools in need of some TLC. It’s a revenue stream that’s helped propel many a tech through an uncertain economy — and one that’s expected to continue well into the current year.

How it unfolds

The routine typically begins with a call to the local health department from a concerned neighbor. Health officials then contact the new property owner, at this point usually a bank or lending institution.

The bank will then notify the Realtor or management company, which has a greater stake in keeping the property clean and presentable.

“Banks want these pools cleaned, filled, and up and running,” says Mary Schreiber, a Realtor with Coldwell Banker in Yorba Linda, Calif. “I just know that when I see a pool in the ground, I need to get it filled. And banks trust me to use people who do what they say they are going to do.”

Schreiber, who has facilitated nearly a dozen “green-to-clean” jobs over the past year, uses local service technicians referred by a fellow Realtor.

Others find work through trade contractors, or companies that specialize in property preservation, real-estate owned maintenance and repair services.

In still other cases, securing jobs may require some old-fashioned legwork.

“I’m pretty well-known around here,” says Dave Durkin, owner of Wet & Warm Home Center in Antioch, Calif. “But for others I’d suggest distributing business cards, or sending out a mailer to local real estate agents letting them know you’re available.”

Durkin has completed some 30 green-to-cleans in the past eight months, mostly across Northern California’s Contra Costa County. He typically charges between $400 and $500 for a comprehensive service.

That price may increase, however, depending on the extent of neglect, or if a spa or large waterfeature is included.

The time required for such jobs also varies, though most agree it’s about a four- or five-day undertaking.

“But during that time you may end up making five or six separate trips to the property to check on it,” says Al Mangin, owner of Dependable Pool Service in Temecula, Calif.

A worthwhile venture?

Riding a steady wave of foreclosures, Mangin contracted about 35 green-to-cleans in the second half of 2008. At upwards of $600 a pop, he has no plans of cutting back. In fact, he anticipates even more business this year.

“And when the house sells,” he says, “you may even pick up the homeowner on service.”

Indeed, Mangin recommends documenting each project with several before-and-after photos. This allows new homeowners to see the transformation for themselves. And it may help convince them to retain the tech for regular service and maintenance.

What’s more, abandoned houses are frequent targets of thieves and vandals. So having an extra set of eyes around the property is invaluable, Schreiber says. And techs often will identify other potential problems — be they maintenance or electrical-related — in and around the home.

It’s yet another reason why Schreiber makes sure her techs are compensated on-time and in full — a frequent concern on jobs involving multiple paying parties.

“We’re all independent businesspeople, which is why I always try to make sure my vendors get paid first,” she says. “They have bills to pay, too. So at any given time I may be several thousand dollars out of pocket just to make sure my pool guys are taken care of.”

But not all banks and Realtors share Schreiber’s approach, which is why some techs flat-out refuse such work. Mike Stinson has taken on a handful of green-to-cleans over the years, “and they’re always a struggle.”

“There are just too many variables involved to make it worthwhile for me,” says the owner of Mike the Poolman in Folsom, Calif.

Among Stinson’s chief protests: Banks and Realtors frequently request a quote up-front, and then just accept the low bidder. Securing payment can take up to several months, and to make matters worse, the pools often are half-full, which creates further challenges.

“You can’t get a feel for how the pump is doing because the pump isn’t primed,” he says. “You may have an air leak, or a clogged impeller. Bottom line is I can’t diagnose what’s wrong with the pool without running water through the equipment. It’s the same reason I can’t expect my doctor to diagnose me over the phone.”

It’s equally important to be clear in your bid, Mangin notes: “Make sure the bank knows exactly what you’re charging, as well as what you’re doing and not doing. You might find leaks, or a bad motor that’s been out of use for many months.

“So you really could be walking into a beehive that you don’t know much about,” he warns.

However, most experts agree that in difficult times, a willingness to diversify is crucial to survival. And with foreclosures in California expected to continue through 2009, there may be no better time to take those pools from green to clean.

“It’s going to be a challenging year,” Mangin says, “so this is a way to replace jobs. It’s a nice supplement in a tough economy.”