DALTON — A ruptured sewer line on Wednesday night was quickly contained and was less serious than initially believed, officials said Thursday.

Crews responded to the broken sewer line at about 9 p.m. and discovered that raw sewage was flowing into a Housatonic River bank at a rate of about 15 gallons per minute.

The workers set up a temporary catchment and pump system on the Housatonic river bank by midnight and contained the leak, according to Catherine Skiba, a spokeswoman for the state Department of Environmental Protection. By 4 a.m., a hard-piped, pump-around system was completed.

"The leak was fortunately much smaller than initially reported as the sewer main was only partially separated," Skiba said. "We are concerned with any discharge but this was much smaller than it could have been as the sewer main only partially separated and Dalton responded quickly."

In a statement released late Wednesday, town officials warned people to avoid swimming, wading and fishing in the river in areas south of Dalton. The river flows through Pittsfield, Lenox, Stockbridge, Great Barrington, Sheffield and Ashley Falls.

The remaining work is to repair the sewer main and additional action may be required on the bank where the discharge occurred, Skiba said. 

"We don’t have any data regarding discharge earlier prior to staff arriving," Skiba said. "Once the immediate repair work is completed, Dalton is required to investigate further to estimate the total amount discharged during the event." 

Haven Orecchio-Egresitz can be reached at horecchio@aberkshireeagle.com, @HavenEagle on Twitter and 413-770-6977.