When Bob Winters heard about Pittsburgh's new rental registration program, he promptly went to the city's Robin Building, Downtown, to pay the $12 per unit fee for his two duplexes. "I had the checkbook ready," he said Friday, while standing in the basement of a property he's now fixing up.

If only it was that easy.

Mr. Winters' effort to register and pay landed him in the kind of regulatory quagmire that no one in city government anticipated in 2007 when council voted to demand the registration of all rental properties.

He has been told to ask the city's Zoning Board of Adjustment for permission to continue renting out a Carrick property. And if permission isn't granted? "I have to basically evict these people and tell them to find another place to live," he said of his tenants. Then he'd try to sell it.

The problem: City officials have determined that the lot for the long-standing duplex is 120 square feet short of the required 3,000 square feet for an apartment building.

Rental registration was one answer council and Mayor Luke Ravenstahl offered to the problem of poorly maintained properties with hard-to-find absentee landlords. The first-ever registrations are due April 1.

Mr. Winters, a Wilkins resident and the director of training for a Monroeville-based medical device firm, said he's not a do-nothing landlord. He started by renting out the Elliott duplex in which he grew up.

He bought a Carrick property in 2002, for $13,000, and put around $50,000 into improvements.

"The intention was to buy basically blighted properties, put some money into them and rent them," he said. "We completely renovated [the Carrick property]."

Its blue siding, white trim and burgundy shutters make it one of the block's standouts.

Allegheny County records list it as a two-family rental home on a 2,880-square-foot lot. Mr. Winters said it was a two-family rental long before he bought it.

"The [owner] before me rented it for years, and the people before them rented it." The utilities were set up for two units, he noted.

When he went to register, though, he learned that he needed an updated certificate of occupancy. Then he was told that he couldn't get one, because city code requires that rental properties have 3,000 square feet of lot space -- and he was 120 square feet short.

"They told me that this property does not qualify as rental."

Courteous zoning staff spent hours poring over the rules with him. "I really only have one option -- to go to a hearing for a variance," he said. He also was told that a parking pad in front isn't legal without a variance.

According to the city code, the Zoning Board can't grant a variance unless it finds that a property can't be developed in accordance with the rules.

Mr. Winters is gathering statements from neighbors, past owners and, he hopes, utility companies in hopes of swaying the three-member board at an as-yet-unscheduled hearing. He may hire a lawyer, though that would guarantee that he will lose money on the property this year.

Of the first 758 buildings for which the city got rental registration applications, 707 lacked valid certificates of occupancy.

When there's no valid certificate, city inspectors have to check the property for safety violations, "and it's a good thing," said Chief of Building Inspection Sergei Matveiev. "A lot of these buildings don't have smoke detectors, which is something that's fundamental for the safety of a housing unit."

Mr. Matveiev said he has no idea how many cases like Mr. Winters' are out there, and zoning officials weren't able to address that Friday.

Some groups representing landlords have said they might sue over the $12 per unit fee and the requirement to provide tenants' names to the city. Individual landlords have objected to the bureaucracy, inspection and $65 fee for a certificate of occupancy. Mr. Winters said he has no problem with any of that.

"The money's not it," he said. "I welcome an inspection ... That part sounds easy. But it's [hard] getting to that point."