LAKEPORT, Calif. (AP) — For months homeowners agonized as houses in their subdivision sank one-by-one into a California hilltop. It got so dangerous that the U.S. Postal Service refused to deliver mail.

Now, they say they know the reason eight homes were destroyed and 10 others are in danger, and they've taken the first step toward recouping damages by filing a claim against Lake County.

A leaking county water system that went undetected for months saturated the hillside and caused the ground to give way, said Michael Green, an attorney for the 41 homeowners in the subdivision with sweeping views of Clear Lake in Northern California.

Green is seeking $5 million for each homeowner in the claim filed last month against the county.

"They're facing a pretty significant economic disaster," he said.

County officials did not immediately respond to requests for comment. They have 45 days to respond to Green's claim for damages before he can file a lawsuit.

Lake County supervisors previously asked Gov. Jerry Brown to declare a disaster area, but the request was declined.

The county has maintained that a landscape irrigation system operated by the Lakeside Heights homeowners association could have contributed to the ground saturation.

As home after home sank into the hillside, bewildered homeowners began to wonder if their land might be haunted.

Eventually, tests revealed leaks "dumping substantial amounts of water into the hillsides," Green said.

He said even the owners of homes not damaged by the sinking earth are suffering damages because they will be unable to sell their property.

"We're just trying to get these folks reasonable compensation," he said.