More than 7 million Americans have taken the plunge and built their own pool. And another 3.4 million relax in their own spa or hot tub. What do they know that the rest of us don't?

The fact is, putting in a backyard pool is not only an investment in your home, but an investment in your lifestyle, according to Jack Cergol, director of communications at the National Spa and Pool Institute in Virginia.

"Pools do add value to your home, and in Phoenix, you probably get back close to 100 percent of that you put into a pool. But it's not as much a money issue as it is a 'quality of life' issue. You derive so much enjoyment from a pool".

In 1997, the National Spa and Pool Institute commissioned a study of current and prospective owners to determine their attitudes about pools and hot tubs.

P.K. Data and Ingals Public Relations found that the majority of respondents considered their pools or hot tubs to be ready remedies for lives that often are too busy to allow for quality time for family, friends, and even themselves.

These liquid assets, they said, offer relaxation, a convenient place for exercise and physical therapy, and they foster togetherness. At the same time, they said, their pools/spas added beauty and value to their homes.

Arizona ranks sixth in the country for the number of inground pools. Only California, Florida, Texas, New York and New Jersey have more, according to P.K. Data.

The esthetic and enjoyment factors aside, pools truly are a good investment. "With the interest rates inching up, some people are staying in existing homes and upgrading their life and living space through artistic use of the backyard," said Mike Smith, President of California Pools.

"The real value in a pool goes beyond whether a family decides to vacation, buy a boat or build a pool. In most of our leisure dollars, the money is lost. In a pool, the money returns in years of enjoyment and use, plus returning the original investment in increased home value," Smith said.

It's little wonder in today's busy world, relaxation and stress reduction were listed among the top reasons most people cited for owning a pool or hot tub. Many people take advantage of the low-impact exercise benefits of their pool.

Swimming is one of the leading forms of exercise in the United States. In fact, swimming was ranked as the most popular recreational activity in American in a study conducted for the Sporting Goods Manufacturers Association.

More than 94 million participants ranked swimming as their favorite fitness activity, putting it ahead of more than 100 different recreational pursuits.

The popularity of recreational swimming is translating into a boom in pool sales. Sales of inground swimming pools has risen 40 percent over the past five years.

If you're thinking about building a pool, most experts advise that you compare companies and options before making a decision.

"The most important piece of advice I can offer a buyer is to choose the right builder," said Steve Rondeau, general manager of Rondo Pools.

"The cost of a swimming pool is determined by many factors. Some people confuse price and cost. If you factor in quality, design creativity, integrity and your stress level, some companies offer the lowest price, but in the long run, your `cost' may be much higher."

For more information about pools, spas or hot tubs, contact the National Spa & Pool Institute