Federal environmental enforcers have blocked Columbia wastewater officials from talking to The State newspaper about one of the city’s largest investments — tens of millions of public dollars used to upgrade its crumbling sewer system.

The Environmental Protection Agency told city officials last week to stop discussing what they have done or plan to do to deal with the deteriorating sewer system, said city manager Steve Gantt and assistant city manager Missy Gentry, who oversees the city’s water and wastewater divisions.

To publicly discuss any aspect of the sewer system risks violation of the confidentiality agreement the city signed with the EPA and the U.S. Justice Department as part of an impending civil settlement, Gantt and Gentry said Monday.

“We don’t want to send mixed messages to the EPA,” Gentry said. “We really want them to know (that) we take the confidentiality seriously.”

The EPA and the Justice Department declined to comment on the written communication, which Gentry said was received on or about Oct. 31. She canceled the latest interview with a reporter set for Nov. 1.

The directive effectively is a gag order on a major public policy issue that involves revenue from ratepayers and years of loans backed by utility rates.

“We don’t, as a matter of policy, comment on ongoing settlement discussions,” said Wyn Hornbuckle, a Justice Department spokesman in Washington. He would not discuss the recent directive nor say whether such action is uncommon.

Yet, City Council is scheduled this week to revisit unpopular water and sewer rates during its annual, two-day retreat. The rates are on Wednesday’s agenda.

Any talk of how a change in rates might affect the settlement would occur behind closed doors.

“We can have discussions with (City) Council,” Gantt said.

“But those discussions are in executive session,” Gentry added.

Gantt said city staff Wednesday will present council with alternatives to the rates that took effect July 1, including availability fees, called base rates, that skyrocketed as much as 28 times the previous rates – even if customers don’t use a drop of water.

But staff cannot address publicly how changes in rates might affect its impending agreement, called a “consent decree,” the city leaders said.

The controversial rates were designed to generate $100 million annually for the next five years, the bulk of it to upgrade the sewer system.

If council backs off on the rates, “You have to find other funding sources or you extend you’re five-year plan to a 10-year plan,” Gantt said.

The newspaper has reported the EPA and the Justice Department are close to fining Columbia as much as $1.5 million for pollution infractions.

Sources told the newspaper last month the consent decree could expose the city to fines as well as millions of dollars in improvements because of wastewater infractions that have resulted from years of insufficient spending on the sewer treatment plant, deteriorating sewer lines and other problems that have violated environmental standards. The settlement is likely to become public early next year.

In December 2008, armed federal inspectors raided the treatment plant near Interstate 77 after being tipped to alleged environmental infractions. No criminal charges grew from the raid, but it exposed the city’s crumbling sewer system.

In the spring 2010, the newspaper documented that the city had diverted $79 million during the previous 11 years from its water and sewer fund to pay for other city services.

Further, City Hall has been sued over those practices. The case, which was to go to trial the week of Oct. 8, has been postponed, said Joseph Azar, a frequent City Council candidate who is one of the plaintiffs.

Gentry and other leaders in the utilities division have conducted a series of interviews with the newspaper, dating to fall 2011. The meetings were to itemize how much money Columbia has invested during the past five years in wastewater improvements and where the upgrades have occurred. Additionally, the interviews were to cover details of the plans for the next five years.

During the past five fiscal years, that system has generated $591.2 million in revenue, according to city budget figures. In addition, during that period, the city has spent tens of millions and planned to spend $281 million more on sewer improvements by 2017, records show.

How much of the upgrades are tied directly to the sewer settlement is unclear and cannot be disclosed until the settlement is final, Gentry said.

Reach LeBlanc at (803) 771-8664.