If Frank Lloyd Wright had been an art collector, he might have designed a house like Benjamin Costello's. If America's most famous architect had been a lawyer, he might have had an office like Mr. Costello's. And if Mr. Costello had Mr. Wright's artistic vision, he might not be a lawyer at all.

"I support artists because I can't do what they do," said the Washington County attorney. "How can they do that? If I could do that, I'd do it all day long."

Mr. Costello, 58, was talking mainly about the many artists whose work is displayed throughout the 4,500-square-foot house in Peters that he shares with his wife, Jan. But he feels the same way about Mr. Wright, whom he calls "a revolutionary ... so far ahead of his time." He first admired Mr. Wright's modern furniture in books, then got to see his masterwork, Fallingwater in Bear Run, Fayette County, about 20 years ago.

"I felt like I could go there and just sit all day," he said, smiling at the memory.

Since then, the couple has returned five or six times to visit the "house on the waterfall" that Mr. Wright designed for Edgar J. Kaufmann Sr. in the late 1930s. They have also visited nearby Kentuck Knob and made trips to Ohio, western New York and New Hampshire to see other Wright houses.

In 1995, the Costellos hired Ed Harmon of F.E. Harmon Inc. in Upper St. Clair to build their Wright-like Prairie-style house on two acres in Peters. Ten years later, Mr. Costello renovated his law office of Yablonski, Costello & Leckie in the historic Washington Trust Building in downtown Washington, Pa., with Wright-designed or inspired furniture, lamps and artwork.

So what is it about Mr. Wright's style that makes this buttoned-down lawyer want to surround himself with it at work and at home?

"It gives me a sense of calm, of order. Your surroundings should demonstrate who you are. When I'm here, I feel uplifted, free, more powerful," he said in his office.

Mr. Costello pursues the objects of his obsession with the steady determination of a lawyer building his case. When he discovered that F. Schumacher & Co. no longer made reproductions of a rug that Mr. Wright designed for Heurtley House in Oak Park, Ill., he turned to Betsy Poole, store manager at Fallingwater, which is run by the Western Pennsylvania Conservancy.

"Betsy asked for one, and it was the Moses effect -- she called and the waters parted!" he said.

Mr. Costello was even able to choose the thread colors -- red geometrics on a pale green background, matching the palette he chose for his law office. Ms. Poole and the Conservancy also sold him a set of six Wright barrel chairs, signed and numbered reproductions made by Copeland Furniture of Vermont, and linked him with craftsman Bill Duerksen of Hamilton, Ohio, who made the rest of Mr. Costello's office furniture. The lawyer loves the desk and credenza's Fallingwater-like cantilevered design and their rift-cut oak craftsmanship. And that rug made specially for the office? It didn't end up under his desk as planned.

"I loved it so much, I took it home," he admitted.

The 8-by-10-foot wool rug now rests beneath the desk in his home office, surrounded on three sides by trios of Andersen windows with Prairie-style inserts. The Costellos love the windows' look but not their design.

"They're buggers to clean," Mrs. Costello said. "You have to take out all the screws and take them apart."

Not so with the arched, beveled-glass double doors leading to the office. Made by California Door Co., they're actually exterior doors, but Mr. Costello chose them to make an interior design statement. He also used Mission-style outdoor fixtures by Arroyo Craftsman Lighting, which can be bought at Cardello Lighting. Lamps in the living room, family room and other parts of the open floor plan were made by Stickley and Tiffany.

Jamie Misencik of Misencik Inc. and finish carpenter Joe Sirlin crafted the beautiful woodwork throughout the first and second floor. Most is oak stained to match interior doors of birch. The Costellos first admired their work in a spec house that Mr. Harmon built elsewhere in Peters. One look told them this was the builder and craftsmen they wanted for their house. They also used Mr. Harmon's architect, Doug Sipp.

In 2003, the couple used a different architect, Robert Stevens, and carpenter, Phil Long of Precision Carpentry and Cabinetry, to finish the basement. With Prairie-style oak woodwork and spaces for TV watching and exercise, the basement has the same open feel as the upstairs. Mr. Costello particularly admires how Mr. Stevens delineated the different areas with ceiling trim and created an accent wall of stone veneer, built-in benches and cantilevered side tables with dentil molding.

"We wanted it to look like Fallingwater," he said. "It doesn't have that finished basement feeling."

Then again, how many finished basements have a grouping of original oil paintings over the stair climber and elliptical trainer? Artwork is everywhere in this house, including its four bedrooms. But it's best displayed on tall spotlit walls in the long corridor that acts as a central axis running the length of the first floor. The corridor is punctuated by two gas fireplaces, one made with tan Roman brick.

Despite that Wrightian touch, the corridor is the only part of the house's design not found in the master architect's houses. Mr. Costello got the idea from the couple's former vacation home in Santa Fe, N.M. In the Southwest, the sala is an open space near the front door for greeting guests. But that's not why Mr. Costello wanted it.

"When we saw it, Ben said, 'That's a really good idea. I could hang a lot of artwork there,' " Mrs. Costello said.

Sharing pride of place are works by local artists Nat Youngblood, Ray Forquer and David Bowers. Down one corridor are several works by Post-Gazette artist Dan Marsula and large paintings by native Brody Burroughs and Russell Hamilton of New Mexico. "Walking Torso," a dramatic nude sculpted in black Tennessee marble by American Indian artist Bob Haozous, stands at one end of the axis just off the family room, where more of Mr. Forquer's works are hung.

The Costellos consider many of the artists and their spouses close friends. They met many through Mr. Costello's chairing of Washington County Historical Society's annual Art in the Garden. The artists often are guests at the parties at the Costello home. This is a great "party house" because its open spaces can be both shared and intimate, says its biggest fan. He believes the man who inspired it would approve.

"If Frank Lloyd Wright came to my house, he'd say, 'Yeah, I recognize this,' " Mr. Costello said. "Of course, he'd probably find something to criticize, too."