There aren't any rules that tell us when a pool can be called a "beach," but most of our beach-type pools have one thing in common: They have no real sides. Instead, you walk in as you would the real beach, with the water getting gradually deeper.

Back in those fantastical times, local "beach" developers often hauled in truckloads of sand to spread around the pool, trying to complete the illusion that you're beside the ocean and no longer anywhere near hot and dirty Pittsburgh. But that sand got into everything, and anyway, grass is often softer and cooler.

One recent hot afternoon, I drove out Route 88 into the far South Hills to the beautifully maintained and refreshingly old-fashioned Mineral Beach near Finleyville. The water originally came from a nearby well and contained a lot of magnesium, which may be why the original owners named it Mineral Beach in 1924. Willis Abel and his family now own and run the place, and Abel's a busy man tending to the pool.

"You couldn't see the bottom of the deep end when I bought it back in '63," he says. "Now the water's crystal-clear. Always. That magnesium left like a bathtub ring on the pool," he says. "Now we're all South Pittsburgh water." One million, 200,000 gallons of South Pittsburgh water in the pool.

The water's not as cold out there as it tends to be at the still-lively and fun Ligonier Beach (with wake-you-up cold water from an artesian well) in Westmoreland County. And in Washington County, the pool-loving Rach family has added a big bucket that fills and dumps water on people at Sunset Beach Park, between Claysville and Washington, right beside Route 40.

A few of the still-popular oldies like Rosedale Beach in Verona and Pine Cove Beach Club (formerly Red's Beach) in Charleroi have become clubs with membership fees, but their 1920s-vintage pools have survived.

Many are gone, though: Stoughton's Beach near Slippery Rock closed in 1975. What had once been the huge Sunlite Pool at Kennywood went out of business in 1973. For some reason, many of the big pools were built south of the city -- closer to the equator? -- such as Cabana Beach and St. Clair Beach and the much-missed Piney Fork Beach, which lasted in Library (now South Park) from 1927 until 1977.

Apparently, we Pittsburghers have long yearned for a big body of water, and while three rivers can be fun, there's a goofy kind of satisfaction you get only at a "beach" in this part of the world. We cool down in pools as big as football fields, spread out our not-so-terrible towels, and if the conditions are right, we catch a breeze blowing in from the ocean of our dreams.

Many thanks to Paul Korol and the folks at South Park Historical Society for their help with this story.