The $4.1 million cost of fixing a broken sewer interceptor that caused a sinkhole to open in mid-September on Middlebelt Road will be shared among communities served by the line.

Oakland County Water Resources Commissioner John McCulloch told Farmington Hills officials Monday at the City Council meeting that his office decided early on to issue bonds to pay for the project. While the county has reserves, he is concerned that the age of the system is putting a strain on them.

"This project is an example of what we're going to deal with in the future," McCulloch said, adding the scope of the work made it "very expensive."

Suzanne Coffey, manager with the Oakland County Water Resources Commissioner's office, said Monday night the WRC was called after a large sinkhole formed on Middlebelt between 12 and 13 Mile roads. She said a closed-circuit camera dropped into the sewer interceptor initially showed no trouble at all.

Three days later, the sinkhole grew larger, and another inspection showed the sewer line had dropped about four feet.

The 36-inch, 60-foot section is part of an interceptor that serves 15 communities. Several factors complicated the project, Coffey said, including a nearby high-pressure gas main and significant ground water that had to be drained away.

In the long term, McCulloch said, the county is looking for funding beyond charging rate payers. He said the federal government used to fund 80 percent of infrastructure projects. Typically, funding came through Congressional "earmarks," or funds guaranteed for a specific purpose attached to general appropriations bills.

Earmarks have fallen out of favor in Congress, but "I think the feds need to step up," McCulloch said.

The county may also look to the state for loans or some kind of subsidy, McCulloch said.