Mary Green lives next door to an abandoned rowhouse in North Philadelphia; it's been vacant since the woman who lived there died 11 years ago.

It shows.

The windows and back door are knocked in and debris litters the first floor. The roof has caved. Since 2008, two fires have hit the building. And with one of the support beams lying in a heap on the floor, the roof over the front porch is listing precariously.

To make matters worse, "vagrants go in and out of there," Green said.

She is also concerned about the damage the building is causing to her own rowhouse. Rats have chewed holes in her wall. Her front porch has started to buckle. And if the house next door, which has a bulging retaining wall, were to collapse . . .

Green said she's been trying to get the city to tear down the property ever since it was abandoned. It was condemned several years ago, but never demolished.

L&I GAVE THE HOUSE A REPRIEVE. We called the Department of Licenses and Inspections, which confirmed that the house was slated to be demolished, when it was classified as "imminently dangerous."

But the building was taken off the demolition list when it was later reclassified as just "unsafe," according to spokeswoman Maura Kennedy.

Demolishing a house costs $17,000. Because the city has limited resources, Kennedy explained, it only knocks down structures that meet the "imminently dangerous" classification - basically, if they're about to fall down. "Unsafe" structures get cleaned up and sealed by the department, and are regularly reinspected to make sure they haven't deteriorated to the point of collapse.

So how did the house next door to Green go from "imminently dangerous" to "unsafe"?

In 2008, L&I went through a process of re-evaluating all the buildings on its demolition list to make sure they all really needed to be there. It ended up reclassifying properties that inspectors decided were not actually about to fall over.

The size of the old list was "unrealistic" and classifications were "less meaningful" than they are today, Kennedy said.

THIS TIME, THE HOUSE COMES DOWN. An L&I inspector had last visited the house next door to Green in June, after the most recent fire, and affirmed the unsafe classification.

After we called and detailed some of the recent developments, L&I sent another inspector out to re-evaluate the property.

This time, it was classified as "imminently dangerous." It should be taken down in the next two weeks.

Kennedy said the structure had deteriorated significantly over the last couple of months, and theorized that bad weather - plus the fact that the seal to keep animals and squatters out of the property was broken - may be responsible.

"If people see deterioration in a property, please call 3-1-1," she said.

Green hadn't called lately, and the next scheduled reinspection wouldn't have happened until April.

Of course, Green stopped calling the city because she got frustrated the house hadn't been torn down. No one had ever explained the reclassification to her. She'd given up.

In a sense, L&I was stymied by its own history in this case. Why call L&I for help if years of previous phone calls did nothing?

Kennedy agrees it will take time to build confidence in the agency, so that residents regularly report problems like this to L&I.

THIS ONE MIGHT BE ON YOU, TAXPAYERS. Though the city will tear down imminently dangerous properties, the legal owner of a property is responsible for maintaining it so it doesn't reach that point in the first place.

In many cases it's difficult to establish ownership of an abandoned property because the previous owner died without leaving clear heirs.

We couldn't find out if someone owned this house. If L&I can, it could sue that person for the cost of demolition. Otherwise, it can place a lien on the house and try to collect if the property goes up for sale.

As for Green, she said she's going to hold off celebrating until L&I actually knocks it down.

We'll check in with her in a couple of weeks to see how it goes.

Dealt with city services lately? How did it go? Let us know at thecityhowl.com, e-mail howl@phillynews.com or call 215-854-5855. And check out this story on the Fox29 News at 10 tonight.

-- Anthony Campisi