Customers of the Rapidan Service Authority, which serves the central Piedmont region of the state, including Orange County, are under a drinking water warning because the water emits an odor. But the question remains: What is causing the smell?

To WednesdayThe Virginia Department of Health and RSA initially issued a water warning, including a swimming ban in the Rapidan River, out of an abundance of caution after residents reported the odor of their tap water.

The smell, which was reportedly reminiscent of diesel, raised fears that oil had leaked into the Rapidan, which flows into the Rappahannock River and is the source of water treated at the Wilderness Treatment Plant before being distributed to customers.

However, after a “comprehensive water sampling,” the VDH found that no volatile organic compounds – such as those found in fuels and household products – caused the worrying odor and that the drinking water continued to meet federal and state drinking water standards.

Nevertheless, the recommendation not to drink alcohol remains.”until the worrisome odor has subsided to a higher level,” said Brookie Crawford, risk communications manager at VDH, on Monday. “The extensive laboratory testing conducted to date does not indicate a risk to public health.”

Brent Hunsinger, director of advocacy and coastal programs for Friends of the Rappahannock, a nonprofit environmental organization dedicated to preserving the Rappahannock River, said no dead fish or water discoloration have been observed.

Since there are no effects on the ecosystem, the source of the odor could be in the infrastructure of the sewage treatment plant itself. But neither a source nor a chemical substance has been identified there either, said Hunsigner, based on his discussions with people familiar with the process.

“It’s a pretty annoying problem,” Hunsinger said, adding that the time it took to solve the puzzle was partly due to a 48-hour testing period for the water.

VDH has planned another inspection of the facility for Monday, Crawford said.

“RSA advises customers who still notice an odor to flush their faucets,” said Dwayne Roadcap, director of the Drinking Water Authority. “The investigation to identify the source and cause of the odor is ongoing.”

Residents who notice the smell in their water can report it at this form on the RSA website.