Barbara Langdon and her boyfriend saw a loft for sale on West 15th Street right before Christmas and knew they'd found a winner. It was in great shape and sprawled over 2,300 square feet, just what they wanted, so they made an offer for $1.75 million that was quickly accepted. "We were excited because we'd only been looking three weeks," Langdon remembers. Soon after, though, their broker called to convey a fussy bit of news: The co-op was entirely nonsmoking, not just in common areas but also in the apartments. "That was the deal-breaker," says Langdonnever mind that she doesn't smoke. "How dare they tell me what to do in my own apartment."

Apparently, they can. "It's absolutely enforceable," confirms co-op attorney Adam Leitman Bailey. "By signing on to a co-op, you're giving up some of your personal rights, and in this case, that would be smoking." Co-ops, after all, have long dictated "house rules," requiring owners to carpet floors, turn off music late at night, and forgo pets. "[They're] small democracies, and if the appropriate majority of shareholders agree on a policy, as long as it doesn't discriminate against protected categoriesand smokers are notthen they can institute and enforce it," says Mary Ann Rothman, from the Council of New York Cooperatives and Condominiums. Sotheby's International Realty's Elizabeth LaGrua, who represents the seller at the West 15th building, says the board put the rule in place because people griped about wafting fumes. "They know from past residents that smoke does travel through the building," she explains.

It's not the first time a co-op has tried to go smoke-free. In 2002, the Upper West Side's Lincoln Towers at 180 West End Avenue instituted a ban on incoming smokers, igniting a flare of controversy; the rule was later rescinded because of the uproar, says lawyer Stuart Saft, the building's counsel back then. (He says he hadn't heard of any other buildings trying it.) Civil-liberties types complained, but an increasingly nonsmoking city may find such buildings more acceptable. Quite a few California buildings already have bans. A recent survey by the New York Coalition for a Smoke-Free City found that more than 69 percent of New Yorkers want to live in a smoke-free building, and that nearly 50 percent would pay more for the privilege. Langdon and her boyfriend, however, are bailing on their deal. "If you can smell what's in other people's apartments, I don't want [it] anyway," says Langdon.