Lake inversion occurs when there are extreme temperature differences between the surface water and the deeper water, which causes turbulence and the organic, smelly sediment at the bottom to rise to the top.
FAYETTEVILLE, Ga. -- Fayette County tap water still stinks, one week after the tap water in many parts of the county began to smell like a sewer.
The county insists the water is safe to drink. As of Monday night there was no telling how much longer the water would continue to stink.
"I noticed it on Monday" May 6, said Lucille Redding of Fayetteville. "Tuesday it was just ridiculous, and each day it gets progressively worse. The smell is putrid, as is the taste.... like a sewer.... It's terrible, terrible."
She and her husband are now on their third case of bottled water.
Fayette County blames a natural event that occurred in one of its reservoirs, Lake Peachtree -- an event called "lake inversion."
"It's just a natural event, it's just like lightning strikes or tornadoes and floods," said Fayette County Commission Chair Steve Brown late Monday afternoon. Extreme temperature differences between the water at the surface of the lake and the colder water below the surface creates turbulence, he said, which churns the organic sediment at the bottom and pulls it to the surface and into the county's water-system intake.
The sediment was filtered out, but the odor remained, Brown said. "There is no harm to your health whatsoever with this water."
Brown said the county is not drawing water from Lake Peachtree for now, but is relying on Lake Horton instead -- pumping treated water from Lake Horton through the system's 600 miles of pipeline.
"We're working on it 24 hours a day. Essentially what you have to do is flush out the system. So in order to flush that much water it just takes an incredible amount of time," Brown said.
But how much longer will it be until the entire system is flushed out?
"I'll be honest with you, we thought we weren't even going to be talking about it today. We thought it was gong to be completely over by now," he said. "So obviously we've got a ways to go."
Brown said individual water customers can speed up the process by flushing their own water lines themselves, but it may be several days before the smelly tap water is flushed out of the Fayette County system entirely.
Anyone concerned about their tap water can receive free testing by the county to make sure the water is clear and free of contamination.