Rick Hoar, an avid boater and jet skier, lives on Aquia Creek in Stafford County, so he can get to the Potomac River from his back yard. But this year, he has left home more often to pursue his hobbies after seeing gunk in the river that looks as if it sprang from a gross-out comic book: huge swaths of bright green algae and some mystery bacteria that hang in the water like "shredded toilet paper."

In search of more pristine waters, he and his son drove Wednesday about an hour southwest to Lake Anna, a 13,000-acre web of coves and inlets created in 1972 by Virginia Power, now Dominion, as a source of water to cool reactors at its nuclear plant.

"This is much cleaner," he said as he fixed a part on his ski. "It's refreshing."

The Hoars represent a tiny ripple of the growth wave hitting Lake Anna as Washington area investors and retirees snap up waterfront property and real estate values soar. But Lake Anna is making its grand entrance as a hot spot just as state and federal officials are planning a serious confrontation with a decades-old topic: water quality in the lake.

Longtime residents say they have been aware of various agencies tracking levels of PCBs, metals and fecal coliform since the 1980s. The state Department of Environmental Quality says the level of PCBs began to rise noticeably in 1994 and fecal coliform in 1998. There is no comprehensive data on metals, though at least one tributary is contaminated. Last week, the agency announced that it will for the first time investigate the sources of contamination in the watershed.

Agency spokesman Bill Hayden said the project is unusual, both because it is being funded by federal money -- in this case, $100,000 from the U.S. Army Corps of Engineers -- and because it is the direct result of a major push by a group of residents.

Fecal coliform, which typically comes from leaking sewage lines or agricultural runoff, has shown up only in Lake Anna's tributaries. Monitors found PCBs -- polychlorinated biphenyls, cancer-causing chemicals used in pesticides and power transformers until being banned in the late 1970s -- in fish tissue. This spring, the state Health Department issued an advisory telling people not to eat carp from the lake more than twice a month -- and telling children and pregnant women not to eat it at all.

Lake Anna's water quality problems aren't considered particularly severe, officials said. Fecal coliform is present "everywhere" in Virginia's waters, Hayden said. Since the Department of Environmental Quality began looking for PCBs in 1998, at least 10 bodies of water in the state have tested high enough to warrant advisories about eating fish. Among those are Potomac tributaries and the James River, which runs through Richmond.

However, Lake Anna's levels "warrant action," said Greg Steele, who will manage the investigation for the Corps of Engineers. Thus far, he said, "there has been no sense of prioritizing and addressing the issues."

Some residents feel there has been a culture of silence about water quality in the 340-square-mile Lake Anna watershed area, where about 23,000 people live -- 80 percent or more of them part time. They suspect it's because business has been booming: The price of one-acre lots has doubled to $50,000 in the last two years, real estate brokers say, and some people don't want to stop the march of upscale, gated vacation and retirement developments and the business they bring.

"All of a sudden, everything has been hush-hushed. The marinas -- it would kill them," said Glenn Briggs, a fishing guide and year-round resident of a section of Spotsylvania County called Bumpass. Briggs said business is great these days, and more people than he can manage want to go fishing with him on his 20-foot bass boat. But he says the fish warning has raised some questions in his mind.

"I'll put it to you this way: If it's contaminated, I wouldn't eat it, and I'm not eating it. As far as doing the sport, that's fine, but as far as eating a whole mess of fish, I'm not going to do that," he said.

In some circles, however, pollution has been Topic A since 1990. The 600-member Lake Anna Civic Association was created 14 years ago to deal with such issues as water quality and boating safety, and three years ago, its members began testing the water to give the Department of Environmental Quality more resources and data. The subject is also a regular in the local newspaper, the Lake Anna Observer, whose Aug. 1 edition quotes people concerned that farmers -- a dwindling species -- are letting their cows wade and make waste in the lake.

But out on the lake, crowding, not pollution, is the more common complaint. Boaters at Sturgeon Creek Marina, in the north-central part of the lake, said last week that they never hear anything about water quality issues, which clearly don't prevent people from flocking here. "On weekends it's like a shopping mall," said James Owens, 32, who lives nearby in Spotsylvania.

A recent Civic Association survey found that people want to slow the river of Washington area transplants. Even people who benefit seemed to concur.

"Business is excellent, though we're not quite where Northern Virginia is, with 15 to 20 contracts on every house," said Liz Wilson, who sells property in some of the dozens of lakefront developments. "But hopefully we won't get there. It's too competitive. We want to keep it laid-back here."

As more water fans turn to 13,000-acre Lake Anna for recreation, state and federal officials are investigating contamination sources in its watershed.