Businesses behind on water bills to the City of Atlanta be forewarned: Your water may soon be shut off.

The Atlanta Department of Watershed Management is planning to send letters to roughly 1,000 delinquent commercial customers who owe the city about $5.5 million combined. Unless the customers develop a payment plan within 30 days, their water service will be disconnected, the agency announced Friday.

The department is pursuing the funds from commercial clients who owe more than $50,000, or who haven’t made a payment in more than a year, city leaders said.

“At the end of the day, commercial customers use water to a profit,” said Mohamed Balla, Watershed’s interim deputy commissioner.

Some of the customers haven’t made water payments in nearly a decade, according to a list of commercial clients released by the city.

Watershed Commissioner Jo Ann Macrina said the move comes as the agency expects a $20 million reduction in its annual revenue because customers are using less water, thanks to behavioral changes and energy efficient appliances. While that’s good for Mother Earth, it’s bad for the department’s bottom line.

“That’s going to hit us pretty hard,” Macrina said. “We have to make up that amount.”

Watershed earns $560 million in annual revenue, with about $10 million in uncollected bills. City officials say while the unpaid bills are a small fraction of the annual revenue, they push the burden to other ratepayers.

“We’re doing this because it’s the right thing to do,” said Mayor Kasim Reed spokeswoman Melissa Mullinax.

Macrina said the department has no plans to cut off water to residential users at this time.

“That’s not what we’re focused on right now,” she said. “…We want to be sure we handle this successfully.”

Macrina rebuffed comparisons to Detroit, Mich., where the embattled city’s water department has made headlines for shutting off water to residents late on their bills.

“The mayor has always focused on a healthy business community, and we have worked with customers no matter what category they’re in,” Macrina said. “That’s very unlike what happened in Detroit.”

For updates, return to AJC.com.