A SENIOR District housing inspector's pronouncement on the conditions he found inside a Southwest D.C. apartment building housing three families said it all: "I've been at a lot of bad buildings, but this was terrible. It was worse than Third World conditions." He was referring to foot-high garbage in one room, feces and urine-soaked piles of refuse in 11 abandoned units and squalor everywhere. "I wouldn't put a cat in there," the inspector said. Maybe he wouldn't, but somehow two homeless families under supervision of the District government's Child and Family Services did end up in the building. How an elderly woman, two mothers and 13 children landed in such a wretched environment is the question that needs answering.

Were it not for D.C. firefighters responding this week to a false alarm in the building, the situation might have gone undetected. Fortunately, upon discovering the deplorable conditions, firefighters took action. The 14-unit building has been condemned, and the families relocated to temporary housing in a motel.

The city's Child and Family Services Agency -- which is under court receivership -- has announced that the two families are being assisted in finding suitable housing. That much is fine. Less clear, however, is the agency's assertion that the families moved of their own accord into a slum building deemed unacceptable by any standard of decency. The building was recommended to the families by a nonprofit agency under contract to the Child and Family Services Agency. A Child and Family Services social worker accompanied at least one family to inspect the unit. Even if the social worker did not technically "place" the family in the apartment unit, which apparently she found acceptable, how could she not have noticed the bad conditions elsewhere in the building?

The questions don't stop there. Inspectors from the D.C. Department of Consumer and Regulatory Affairs inspected the building months earlier, but did not shut it down. Why not? With reporters and TV cameras on the scene this week, inspectors sprang into action, declaring the building uninhabitable. Is that what it takes to get city officials moving?

This case points up a harsh reality that the mayor and council can't avoid. There are fragile, barely functioning families in the District who live in conditions unfit for animals, who are part of communities where children can drop out of school and not be missed and who are under the care of social workers who see the terrible state of affairs and don't bat an eye. Changing that reality is the major social challenge.