Ron Johnson and wife Jane celebrate his primary victory last year in Oshkosh, Wis. — where they also have a home, when not on Capitol Hill. (Morry Gash/AP)

But senators are a different matter. They’ve got at least six years to work here, which makes buying property in D.C. both a practical and financial consideration. Case in point: Sen. Ron Johnson, who lives in a $1 million house near Capitol Hill.

News of the 2,430-square-foot (three bedrooms, 3.5 bath) home, purchased just a month after Johnson took office in January, didn’t become public until reported by Milwaukee’s Journal Sentinel last month. Technically, he rents the property; it’s owned by the Ronald H. Johnson and Jane K. Johnson Irrevocable Endowment Trust, a family trust.

“Hard assets like real estate have historically been good long-term investments,” press secretary Brian Faughnan said in a e-mail.“Senator Johnson maintains his primary residence in Oshkosh, Wisconsin.”

Dan and Marsha Coats, who first bought a house in McLean in 1981. (Darron Cummings/AP)

We asked the other freshman senators about their D.C. digs. Most of the homeowners have been working in the nation’s capitol for years: John Boozman bought a place in Alexandria when he was in the House; Former House Minority Whip Roy Blunt just found a place in Kent after living for years in Georgetown; Dan Coats, who’s been in and out of office for the past three decades, bought his first home in McLean just months into his first House term (way back in 1981) and now lives in a Falls Church townhouse; property records show that Rob Portman’s wife bought a Capitol Hill condo in March.

Rand Paul, center, with Kelly Ayotte and Ron Johnson on Capitol Hill in June. (J. Scott Applewhite/AP)

But they’ll probably end up buying something, too.

“Senators usually buy,” said Terri Robinson, a broker at Long and Foster and former aide to Ted Kennedy. “It’s awkward to rent” for six years, she told us; given the lowest interest rates in history “we’ll see more purchasing.”

Read earlier: Big names trade tiny condo: Capitol Hill pad passes from Boxer to Sanchez to Brown, 10/22/10