The water's too cold. The path's too long. There are too many rocks. And worst of all, you can't get a parking space.

On an Island with more than 100 miles of coastline, these are the complaints fueling the most ironic of businesses - the construction of swimming pools.

Going to the beach, it turns out, has become a huge hassle, especially for the now graying baby boomers. Luckily, they can afford the antidote, and they are ponying up the money for pools like never before.

In Edgartown alone, the building inspector has handed out 21 permits for new pools in the last two and a half years. In West Tisbury, 19 new pools were built in the same period.

That's good news for pool companies, which are doing a brisk business. Island Pool and Spa, based in West Tisbury, builds a dozen gunnite pools a year at about $80,000 a pop. Vineyard Pool and Spa at the airport business park specializes in vinyl pools, which are much cheaper to build, costing a homeowner roughly $30,000.

Islandwide, there are now more than 500 swimming pools sitting in people's backyards, estimates Elmer Silva, owner of Vineyard Pool and Spa. His outfit services 225 of them.

Mr. Silva grew up on the Vineyard and can remember when things were different.

"When I was a kid if I wanted to go to Lambert's Cove beach, I'd just go up there. We could park anywhere we wanted," he said. "Now you can't get to the beaches, and I can't go to Lambert's Cove or Lucy Vincent."

But the thorny issue of private beaches or town beaches closed off to nonresidents hardly seems to be driving the swimming pool boom. After all, even in Chilmark where residents enjoy access to some of the most spectacular oceanfront on the Island, homeowners are putting in pools - nine in the last two years.

What's more, people who own waterfront property, whose doorstep is a stone's throw from the ocean or pond, are also building swimming pools. Edgartown contractor Harry Garvey has built six waterfront homes in the Katama area, all with pools.

"Everyone wants one nowadays. I've been building here 25 years. In the first 15 years, we didn't install a single pool. The last 10 years, they all want one," he said. "It's the convenience of staying home and not going to the beach. There's no traffic, and they can take an early morning or after-dinner swim."

Indeed, convenience is the key motivator.

Kevin Selby of Edgartown got tired of driving up and down Beach Road looking for a place to park so he could spend the day with his wife and daughter at State Beach.

"It's always been State Beach because of the waves and undertow on the south shore," he said. "But we'd have to get up so early to get a parking spot."

Mr. Selby, a builder, decided to construct his own pool, vinyl-lined with a concrete bottom, and spent about $20,000.

"It's like bringing the beach to us. My backyard is my oasis," he said. Heated by gas, his pool stays open from May through October. His daughter just had her 10th birthday party in the pool with more than 20 friends.

"She's popular, let's put it that way," Mr. Selby said.

Over in Vineyard Haven, Douglas Cramer, the television producer of such shows as The Brady Bunch and Wonder Woman, just built a pool on his waterfront property on Kuffies Point at Lake Tashmoo.

"The reason we put the pool in was primarily for exercise. It's too shallow to swim in Tashmoo," he said. "Even with beach access and a key to some of the greatest beaches in the world, a pool gives you more immediacy."

"A pool is more friendly," said Peter Rosbeck, a developer in West Tisbury. "There are still creatures out there in the big Atlantic, and some people aren't totally comfortable with that. It's also friendly from the standpoint of temperature. The ocean is cold, and if you're going to swim for health, it's hard to get yourself up on certain days to jump in the ocean."

In many cases, Mr. Rosbeck said, people who choose to build a pool here already have a pool back home. "Many of those folks have a pool somewhere else, and they got used to it," he said.

But the proliferation of swimming pools signals a shift in the Island seasonal culture. Convenience didn't used to be the paramount goal of people who chose to spend a summer here.

"To me, it's such a strong indicator," said Derrill Bazzy, a builder for South Mountain Company and a member of Aquinnah's affordable housing committee. "People 30 years ago came here partially because of the inconvenience. You came here to have a shack in the woods, maybe without electricity, and to show your kids a simpler life and to be a part of the community. Now there's just a different sense of it, a sense of coming here and being more comfortable."

To be sure, the advent of more pools on the Vineyard has set off a small backlash, raising the hackles of some people who just can't understand the need for them in a place brimming with beaches and ponds.

"Who needs a swimming pool when you live at the ocean?" said Fred Littleton, a member of the zoning board of appeals in Chilmark, where pool applicants must go to win a permit. "They should never have been allowed in the first place. It is too much Hollywood."

Mr. Littleton wasn't naming names, but two of the more recent pool permits in Chilmark went to actor Ted Danson and the television sit-com creator Larry David.

In both Chilmark and Aquinnah, officials are beginning to see swimming pools in both environmental and social terms.

"We saw the impact of swimming pools on the banks of Menemsha Pond and became very concerned. It was necessary to protect the pond from the overflow of chemicals that would end up in the water table and the shellfish beds," said Aquinnah planning board chairman Camille Rose.

In Aquinnah, pools are banned from the coastal zone of ocean and ponds, anything within 100 feet of the waterline.

In Chilmark, voters backed new zoning bylaws that required applicants to live in a dwelling for two years before asking for approval for a swimming pool. Permits granted would not be transferable to another owner. Bylaws also stated that pools "will not interfere with the enjoyment of the natural surroundings" as seen from a public way, public land or an abutting lot.

"We wanted to limit [real estate] speculation. We didn't want somebody to get a permit and sell the house with the permit," said Bob Lunbeck, a member of the Chilmark zoning board.

His board was concerned that while swimming pools might reduce the crowds at the beach, they didn't fit the town's rural character. Applicants were used to living in other places where everybody had a pool in the yard.

"We wanted them to settle in a little bit, get acquainted with the neighbors," Mr. Lunbeck said. "We wanted people to get out in the community instead of hanging around the pool."

From an environmental perspective, Mr. Littleton sees pools placing a burden on groundwater. "We don't have an unlimited supply of water," he said. "We make them get their first filling off-site in Edgartown from a water standpipe so it doesn't deplete surrounding wells."

It takes about 30,000 gallons of water to fill a standard 20-by-40-foot pool. But Mr. Silva said most of the newer pools on the Island are much bigger. "Some of these houses have huge pools, 20 by 66 or 75 feet long," he said.

To fill a pool that size could require almost 60,000 gallons, he figured.

Pools that big are also a little harder to hide from view. Two years ago, Miles Jaffe objected when his neighbor on Stonewall Pond in Chilmark decided to build a pool.

"It was one of these mega-houses," said Mr. Jaffe. "And it was literally 50 feet from Stonewall Pond. He was trying to hide the pool, but it was basically impossible."

The zoning board rejected the request, but Mr. Jaffe is still concerned. To him, swimming pools point to a disturbing trend in which the Island has become a setting for trophy houses and real estate investment.

"We're sort of the gold coast here," he said. "Bigger houses demand more and more services, more pool maintenance people. It's the suburbanization of the land. We are surrounded by neighbors who have so many houses they can't possibly occupy most of them for more than a couple weeks at a time."

On the flip-side, pool owners couldn't be happier. It's even better, said Tisbury architect Peter Breese, when the pool is near the ocean. "It's so cool to have that layering of your water and their water," he said. "You want them both, beach and pool."

"It's the best thing we ever did," said West Tisbury resident Susan Oken, 61. "I swim twice a day. It's clean and it's beautiful." As for Lambert's Cove beach, who needs it? She didn't even bother to get a beach sticker this year.