BLACKFOOT — A collapsed sewer line in Blackfoot damaged several homes on Monday and caused city officials to issue a reverse 911 call asking residents to reduce wastewater output for 24 hours.

When workers arrived on Monday, they discovered that the flow to the wastewater treatment plant on Riverton had stopped, Mayor Mike Virtue said. Further investigation revealed that a 24-inch sewer line had, for unknown reasons, collapsed in the area.

“It caused the flow to backup,” Virtue said, adding that they were able to temporarily bypass that portion of the line to get the wastewater flowing back to the plant, but they were still working to repair the actual sewer line at press time. They hoped to have the work completed by midnight.

City officials issued a reverse 911 call to people in Blackfoot, Moreland and Groveland on Monday, alerting them of the problem and asking them to reduce the amount of wastewater they were using through laundry, bathroom and kitchen facilities for 24 hours to give them time to make the repairs. But for some, the notice came too late.

Joan Thompson, who lives on Riverton, said she was out of town on Monday morning, but her sister, who was taking care of her home, called her to tell her that wastewater was seeping into her basement.

Thompson said the wastewater was already flooding the basement when her sister stopped by the house to drop off the mail and discovered the problem around 10:30 a.m.

“I still have about four feet (of wastewater) in the basement,” Thompson said Monday afternoon, adding that she arrived home to find her furniture, books, antiques, photos, genealogy records and her grandmother’s cedar chest all floating in the contaminated water.

“I think we were hit the worst,” she said, adding that she wishes she had been notified soon enough to plug the drains in the sink and shower in her basement. “It’s like a nightmare.”

Thompson called a cleaning and restoration business to help pump out the water that was still seeping through the drains on Monday evening. She said she remodeled the basement four years ago, but was told that it will have to be gutted due to the contamination.

“It smells really strong,” she said, adding that she planned to stay in a hotel on Monday night because the alarm on her carbon monoxide detector kept going off.

Virtue said other homes were also impacted by the wastewater on Monday, despite workers’ efforts to get the wastewater flowing again as quickly as possible. He didn’t have an exact count on the number of homes impacted, but he did say those affected can call 785-8600 to file a claim with the city offices.