It’s not every day the composer of the Broadway musical you’re preparing for a college production shows up at your rehearsals. But that’s what happened for the cast of Urinetown the week before it opened at UMass. Mark Hollmann spent several days in the Valley, where he sat in on rehearsals, gave a public talk in the Theater Department, and conducted a master class for songwriting students at Amherst College.

I sat in on one of those rehearsals too, and chatted with him during a break. Turns out he wasn’t just passing by and decided to look in to see if they were doing it right. He and the show’s director, Gina Kaufmann, had worked together on one of Hollmann’s early musicals in the 1990s, and Kaufmann took the opportunity to invite her former colleague into her process.

Hollmann has checked out other regional productions of the show, which won Tonys for him and co-author Greg Kokis in 2002. But he said it’s a new experience to participate in a chunk of the rehearsal process, and to be asked for feedback on music and staging—an experience he found “unexpectedly fulfilling. I didn’t know I had such opinions about the show till I’m in a situation where I get to have some input.”

The hit show with the funky name is an exuberantly unlikely mix of substance and style. Set in a day-after-tomorrow dystopia where water is so scarce you have to pay to pee in public facilities, the piece travels on two tracks simultaneously. It’s a satire with a sharp political and ecological message, and it’s also a send-up, not only of its own melodramatic plot—the heartless tycoon who buys politicians with the profits from his public urinals monopoly vs. the downtrodden 99-percenters who rise up for the right to pee free—but of the song-and-dance conventions it’s wrapped in, with cheeky nods to such icons as Les Miz and West Side Story.

“I’m having to restrain myself from trying to replicate other productions,” Hollmann told me. “Sometimes those old choices are the best ones, but there are some really nice new ways of looking at the material in this production that have made me rethink certain parts of the show.”

Indeed, the finished product that opened last weekend holds its own with the New York template, matching its audacious diversity with inventions all its own. Kaufmann’s high-energy production scores on all fronts, from Paul Dennis’ witty choreography, to Andrew Lichtenberg’s musical direction of a tight five-piece combo, to Madeleine Maggio’s harsh steel-and-cardboard set and Emily Taradash’s costumes that embody the gulf between rags and riches, to a gifted cast exceptionally well-suited to their roles.

Among these are Brianna Heffernan as the tough-as-nails privy gatekeeper; Christian Tyler Hoots as the Trump-like plutocrat; Sam Perry and Melissa Ennulat as the cross-class lovers, he the chisel-jawed rebel and she the pampered princess; and Kate Jones as the wide-eyed waif who provides the show’s convention-mocking commentary with Noah Simes’ blisteringly funny narrator/cop.

Through March 10, Rand Theater, Fine Arts Center, UMass-Amherst, (413)545-2511, umass.edu/theater.

Chris Rohmann can be reached at StageStruck@crocker.com.