They used to be one of the hottest things along the Wasatch Front.

Once, hordes of swimmers and bathers enjoyed hot spring resorts. Most of these resorts traced their roots to the pioneer era. In the first half of their 20th century heyday, there were eight such hot springs stretching from Box Elder County to Utah County and from Morgan to Wasatch counties.The first, Beck Hot Springs, was used very soon after the Mormon pioneers arrived in the valley. In fact, it was the influx of gold-seeking 49ers in 1849 who loved the water that prompted Brigham Young to appropriate $6,000 for a public bathhouse there.

The hot springs, believed to have healing powers, were a great source of relaxation for those stopping in Salt Lake City -- the only sizable settlement between Missouri and California in 1949-50.

Rates were $1 for two to four people and $3.50 for a group of 16-24 people.

"It came to be a wonderful place for the Mormons," Utah historian Brigham Madsen said.

Today, only two hot springs resorts (both located in Box Elder County) remain -- Belmont Springs in Plymouth and Crystal Springs in Honeyville.

Why did the other six die out?

The post-World War II generation abandoned them for a new world of many diversified interests like TV, movie theaters and sporting events.

Jonathon Bronson, manager for Crystal Springs, said it has been difficult to stay open. The resort has had a lot of owners since Walt Chamberlain opened it in 1901.

"We have a loyal following," he said, referring to regular patrons who comprise some of the 200,000 people who annually visit Crystal Springs.

Also, the camping resort as well as the waterslide have helped Crystal survive.

Bronson said Crystal's latest owners -- four Virginia businessmen -- plan to add some 20 cabins on the resort's south side this year or next to further its diversification.

Britany Holmgren, manager of Belmont Springs, believes rising insurance and liability rates have been the main reason for resorts closing.

"We have such a problem with people breaking in to skinny dip," she said.

With one pool 35 feet deep, liability is a key issue there.

Besides escalating insurance premiums, upkeep is also high for hot springs resorts. Piping wears out quickly from the mineral water.

Holmgren agrees that better indoor plumbing and more home hot tubs hurt the business of hot springs resorts. So did the belief by many that the mineral water didn't really have healing powers after all.

She said now there's a revival going on and many are coming to Belmont who believe again that the water has some healing properties.

Holmgren attributes the survival of Belmont to a diversification.

Today, it is a haven for scuba divers who use its 90- to 100-degree pools in all but the hottest of summer months. Raising lobsters is also another profitable sidelight for Belmont.

In fact, the scuba diving and lobster raising make more money for the resort than the hot pools do. Belmont also has a nine-hole golf course and camping and RV hookups.

Two of the historic hot springs resorts, Rainbow Gardens in Ogden and the Homestead (formerly Schneitter's Hot Pots) in Midway, have modified themselves dramatically to stay viable.

For example, Rainbow is into hot gifts now, rather than hot water. Robert King of Rainbow Gardens said the resort was losing money in the late 1960s and closed its indoor and outdoor pools. Today, the former indoor pool is terraced into part of the Rainbow Gardens gift shop.

King's not sure why people stopped coming but said perhaps it was all the competing interests.

The Homestead actually rediscovered some of its hot spring beginnings in the past few years with warm water scuba diving. The Homestead also has golfing and lodging as its primary focus.

The Utah Hot Springs (also called Ogden Hot Springs) in Pleasant View closed in about 1970. Wasatch Warm Springs/Beck Springs in Salt Lake City hasn't been used for swimming since 1976 and has housed the Children's Museum of Utah since 1981.

Como Springs in Morgan shut down in 1985 after a 1980 fire, 1983 flood damage and decreasing profits made it too costly to maintain. Saratoga, on the shores of Utah Lake, ceased operations in the early 1990s.

There's also Lava Hot Springs, Idaho, some three hours north of Salt Lake City, that still thrives as a hot springs resort town. But it, too, has had its ups and downs and had to change with the times to survive. It added an Olympic-size outdoor pool in 1972 and broadened its focus to other activities, like miniriver running.

Today, Utahns prefer the waterslide type atmosphere, too. This is evident by Lagoon-a-Beach at Lagoon, Cherry Hills resort in Fruit Heights, Raging Waters in Salt Lake and Seven Peaks Water Park in Provo.

Indeed, Crystal Springs opened a water slide in 1981 and has the state's only year-round slide.

Why do these eight hot springs exist in northern Utah?

Paul Jewell, associate professor of geology and geophysics at the University of Utah, said the Great Basin is an area where the crust of the Earth is being stretched. That makes the crust thinner and means the mantle of the Earth, a warm layer, is closer to the surface.

Water circulates through the crust of the Earth and is heated at these shallow depths. With some good natural plumbing, these hot springs are usually associated with breaks along segments of the Wasatch Fault.

It is also worth noting there are a few other, lesser-known hot springs in northern Utah. For example, "Stinky Springs" is located near Thiokol, west of Brigham City. It was never developed commercially, and vandals have now destroyed its makeshift facilities.

Cache Valley also used to have Loganna in Logan. However, by the early 1980s, this waterslide/swimming resort was sold to accommodate a housing project.