JACKSONVILLE, Fla. -- A Middleberg woman has a sinking feeling the groove in her backyard is a sinkhole.

Pam Coates noticed the dip that she says extends about 20-feet long back in January, but didn't think anything of it until a few days ago when she noticed another hole.

"I don't want to sink in the hole I don't want to be in the house as it sinks because the whole main water line is exposed," said Coates.

She's referring to the water line of the pump house which she said is now damaged after more than a month of continued growth.

So, we looked into it and had Rob Martin,a geology professor at Florida State College take a look at the video, which in his opinion doesn't have all the circular hallmarks of a sinkhole but something is changing the landscape.

"This is more linear that tells me that there maybe something underneath there that is collapsing down an old tree trunk, an old pipe, an old storage facility that's collapsing down I can't rule out a sinkhole but can something as mundane as an old pipe," said Martin.

The problem is that Florida is sitting upon thousands of feet of limestone which is easily dissolved in acid. So, a little bit of water with a little bit of acidity, running through the rock, will carve out caves.

As long as the water stays in the rocks it's stable but if the water comes out of the area, everything collapses into a sinkhole.

Florida law requires insurers to cover "catastrophic ground cover collapse" but the damage caused by a sinkhole might not be in the policy.

So homeowners can purchase additional coverage for things that aren't as obvious as a hole, like cracking in the foundation.