An advisory against using water from Whitesburg's system won't be lifted until at least Wednesday, according to the state Division of Water.
An estimated 3,000 households in Whitesburg and parts of Letcher County have been warned against using the water for drinking, cooking or bathing since Feb. 16.
A diesel-fuel spill contaminated the city's raw-water source, the North Fork of the Kentucky River.
State officials have heard reports of people using the water for bathing despite the advisory. People should heed the warning and not use the water for anything but flushing toilets, said Allison Fleck, spokeswoman for the Division of Water.
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There are health concerns about using water contaminated with diesel fuel, Fleck said.
Letcher County Judge-Executive Jim Ward said the water outage has been a big burden.
"All of us are frustrated that this is continuing, the schools, the medical facilities, and all the people that this has affected," Ward said in a statement. "We can't wash our clothes, can't shower and have to cook out of gallon jugs."
The fuel allegedly leaked from large, damaged petroleum tanks stored at a site on the river upstream from Whitesburg.
The state has cited Whitesburg businessman Don Childers over the leak, saying he owned the tanks. Childers' company owns dozens of gas stations on the area.
Test results from water samples taken last Thursday and Friday showed there were still detectable levels of diesel contamination in the water system in Whitesburg, Fleck said.
Employees started flushing the system Saturday, something they couldn't do earlier because detectable levels of diesel were still coming into the water plant, Fleck said.
Tests at mid-week showed concentrations of diesel fuel in the system four times greater than the maximum recommended for drinking water by one federal registry, she said.
The state is having the water tested with a method that takes three days to complete. That means results on samples taken after efforts to flush the water system Saturday and Sunday aren't yet available.