This article was published in the Lenoir News-Topic.

More than 100 businesses have been told they are due for an upgrade that could cost them up to $25,000.

Affected businesses received a backflow compliance notice from the city informing them that their fire sprinkler line had an outdated check valve, and giving them 90 days to have it replaced.

The check valve is the part of a fire sprinkler that allows air and other gases to flow through. Having it replaced can cost $5,000 to $25,000, according to Mark Eckard of Unifour Fire & Safety, a company that has installed new check valves for six Lenoir businesses in recent months.

Without a backflow preventer, the same mechanism that lets air through can allow chemicals inside the sprinkler system to back up into the public water supply. Some fire sprinkler lines contain antifreeze and other chemicals to prevent freezing or corrosion in the lines. When old-style check valves are being used, it’s more likely a sudden drop in water pressure could cause those chemicals to siphon into the public water system, said Radford Thomas, Lenoir’s director of public utilities.

Beyond that, the old devices are untestable, so businesses without an RPZ valve can’t meet the state requirements for yearly testing.

“That’s why this is an important thing to do,” Thomas said. “We’re trying to protect the public health and safety. It’s not just some arbitrary decision that someone made.”

When businesses were notified, the city pointed to state law as the reason for the change.

“Per the ‘Administrative Code’ for the state of NC these valves have to be replaced with a testable Double Check valve or RPZ,” the notice reads.

The N.C. Department of Environment and Natural Resources’ rules governing water supplies state that fire sprinklers with booster pump facilities or chemical additives require a device called a reduced pressure zone (RPZ) assembly or an air gap to prevent backflow.

The law isn’t fresh on the books. The law requiring an RPZ assembly or air gap was last amended in 1990, said Bob Midgette, an engineering supervisor for the DENR.

What businesses are seeing is not a new law but an effort by the city to get them up to code.

“We started implementing this program some time back,” Thomas said. “We’re just trying to take a few of them at the time, but we do have our plan in place to administer the state law and try to get everybody in compliance.”

Businesses that weren’t in compliance were first notified in 2011. Those that didn’t respond received another notice this year.

About 90 businesses are currently complying with the backflow prevention program, Thomas said. Another 35 have been identified and told they need to comply.

Since the price of the upgrade can reach five digits, some business owners have balked. To a degree, the city is willing to work with them, he said.

“We are seeking a good-faith effort on the part of the business to make the necessary changes in a reasonable time frame,” Thomas said. “We try to take into consideration any budget requirements of the business.”

What his department is seeking more than anything is communication, Thomas said: City officials need to know each business’s plan for replacing the check valve, and it needs to be done as soon as possible.