It's probably not a legitimate "dry run" when it involves a bunch of garden hoses, sprinklers, PVC pipe and 100 gallons or so of water but that's what Pioneer Theatre Company technical director David Deike and his crew conducted several days ago while they were trying out their rain-making system for PTC's season finale, "Singin' in the Rain."

The show opens Wednesday and continues through May 14.I spent part of one morning this past week prowling around the PTC's Lees Main Stage, anticipating that there would be a complicated, high-tech method for re-creating on stage one of the most famous scenes in film history the scene in which Hollywood hoofer Don Lockwood (Gene Kelly in the MGM movie and Todd Taylor in the PTC stage version), dances and splashes his way along a rain-soaked Los Angeles street.

I thought of "The Little Shop of Horrors," and the fact that the originators of that stage musical (it, too, based on a classic movie) have an ironclad contract with whoever is producing the show that intricate blueprints for building Audrey II, the man-eating plant must be followed to the letter. Period.

But such is not the case with "Singin' in the Rain."

Deike was on his own as PTC's resident rainmaker. (Hmmm . . . maybe they could do "The Rainmaker" next season and recycle the equipment.)

Deike, a University of Utah theater department graduate who's worked for the theater for 13 years, loves the excitement and challenge of figuring out ways to make things work, then putting them into operation.

Although he graduated from the U. with a masters of fine arts degree in directing, Deike is happiest back stage, supervising the technical aspects of set construction.

And "Singin' in the Rain" gave Deike, and set designer George Maxwell, plenty of challenges. The musical, one of the largest undertakings at PTC in several years, has 22 different scene changes (part of 14 different scenes), 110 fly cues and from 200 to 250 different lighting cues spread over about 2 hours and 45 minutes. The theater's lighting is computerized, but the rest of the backstage activity is not.

Stage manager D. Dale Dean will be directing all of the behind-the-scenes traffic 32 performers and 34 backstage personnel.

Deike's apparatus for creating the rainstorm is really quite simple.

"Most people are surprised to discover that many of the things backstage are just simple applications of everyday situations you'd find at home," said Deike.

"It's not complicated. In concept . . . it was just like putting a sprinkling system in your front yard. We used very traditional methods, except that we put it 20 feet up in the air," he said.

One request they had was that the water had to be warm, so Todd Taylor, the star performer, "doesn't catch cold from getting doused every night."

Deike said "We started talking about getting a tank to heat the water and chlorinate it and all that, then we came to the conclusion that it was too complicated. We didn't have that much money to invest in a rain machine."

So how does the rain work?

Well, Deike and his workers got some PVC pipe, and hooked up a variety of sprinkler heads most a semi-circular pattern that will confine the raindrops to the moveable unit on which Taylor does his "Singin' in the Rain" routine.

The pipe is hooked to a sink in the workshop with a garden hose. A blend of both hot and cold tapwater is used, so Taylor won't (a) catch pneumonia, or (b) get scalded.

It looks like turning the water faucets on and off is about as technical as it gets.

The sidewalk and storefront where Taylor dances are one large unit on wheels. The sidewalk and street (including a half-inch deep "puddle" alongside the curb), both slope just enough so that the rain runs off into a drain then into another garden hose and out the back of the set into a sink beneath the stage. Parts of the stage have been water-sealed ("just in case") and there's some plastic lining here and there to keep things from getting too wet.

When we talked to Deike, the "dry run" had been held without Taylor jumping around in the puddle so he couldn't really vouch for whether or not patrons in the front rows will get splashed. I'm sure it won't be a "Shamu, the killer whale" experience like the shows at Sea World, where people in the "splash zone" seats get drenched. But if you're in Rows 1 or 2, you might want to stash an umbrella under your seat, just to play it safe.

"We were worried about Taylor slipping," said Deike. "We had that trouble with `My One and Only,' because they were dancing in a trough of water and slipping all the time, so we made the surface rougher but that didn't work because they were in their bare feet, so we went back and sanded it down. We took a different approach with this. Instead of using fiberglass (as in `My One and Only'), we just painted the set with a waterbase paint."

It took about 4 1/2 weeks to construct the street set for the "Singin' in the Rain" number. From the front it looks like a sturdy, typically Spanish-style Hollywood building from the '30s, but in reality the red-tiled roof is constructed from cardboard and the walls are merely cloth nailed to a lumber framework.

Usually, old sets are dismantled and the lumber and hardware are recycled in other sets, Deike said, "but I anticipate that since the tiles are cardboard and the walls are cloth, that this will end up being one soggy lump by the time we're done with it."

With 30 separate flies (the backdrops that hang from the ceiling and `fly down' as needed for different scenes), Deike will have six people on the second-level fly floor just to manipulate this end of the show.

As if flies and rain didn't pose enough problems, Deike and his helpers also had to go into the movie-making business. They had no previous training in movies, so they spent a day learning how to do that. Actual movies are utilized in four scenes. A rented 16mm projector will be placed in the lighting booth.

The stage adaptation closely follows the screen version, so much so that the script even uses such Hollywood phrases as "dissolving" from one scene to another something stage performers don't do.