When Doug Coffey took over one of Florida’s most notorious assisted-living facilities, the home was on the verge of collapse.

Narcotics were being looted from the facility, drug dealers were sneaking onto the grounds to sell crack and its manager had just been hauled away by Pinellas County sheriff’s deputies on neglect charges.

With prosecutors mounting a campaign to shut Rosalie Manor, Coffey was forced to confront a host of problems that had been building for a decade at the string of cottages near downtown Dunedin on the west coast of Florida.

“It was uncontrolled chaos,” said Coffey, a former reserve deputy with the Pasco County sheriff’s office. “I don’t understand why this place wasn’t shut down earlier, but it’s mine now. We got to do something.”

In the next two years, the 59-year-old administrator instituted a series of changes to provide unprecedented care to the residents while struggling to keep the doors open.

In time, the home was not only allowed to keep its license, but it incurred just a fraction of the violations that had once made it one of the state’s most dangerous facilities.

“I didn’t think he was going to make it,” said Karen Lakritz, a leader of a state-funded team that places people with disabilities in homes. “The place was a disaster. It was god-awful. But he managed to do it.”

Experts say the changes at the 40-bed home that caters mostly to people with mental illness represents a dramatic turnaround at a facility where police were regularly rounding up residents and investigating crimes.

Coffey’s first crisis emerged weeks after he bought the home in 2006, when the man still in charge — former owner Erik Anderson — was arrested for endangering the lives of residents, including leaving a former psychiatric patient in charge of dispensing narcotics.

With Anderson out of the picture, Coffey was faced with the specter of cleaning up the home, including stopping drug dealers from coming onto the property and keeping residents from running away.

Several times during his first year, he said he was forced to jump into his truck to track down residents with mental illness who had wandered away.

Though he had owned five assisted-living facilities in the past, he said turning Rosalie around was “the hardest thing I’ve ever done in my life.”

He began by changing the name to Dunedin ALF, partly to get away from the bad publicity that overshadowed the home after Anderson’s arrest.

Then, he faced clearing up more than two dozen regulatory violations incurred before he took over, including residents failing to get crucial medications, untrained staff and a woman using a dirty syringe to inject herself with overdoses of painkillers. “I was looking at 88 pages of deficiencies,” Coffey said.

He fired three troubled staff members and canceled the home’s arrangement with the jail diversion program, clearing the way for eight new residents. His staff began cleaning grime from the walls and floors and putting on a fresh coat of paint. The worst problem: an infestation of German roaches.

He invested in new furniture for residents, throwing away urine-soaked mattresses and torn bed linens.

Next, he said he got training for his staff on dealing with people suffering mental illness, and imposed new rules, including a ban on physical punishment. “There has to be an underlying level of compassion,’’ he said. “They’re people.”