The Regional District of the North Okanagan has been found guilty of four charges under the Water Act and the Drinking Water Protection Act.
No one reported getting sick, but nearly 4,000 people were left without potable water in the Coldstream area for nearly a month in January 2010 when E. coli and other bacteria seeped into a well system east of Vernon.
The contamination happened after a torrential downpour caused flooding in the area.
Patrick Nicol, board chair for the Regional District of the North Okanagan, said the district spent $70,000 on legal fees fighting the charges.
"We thought we had a very strong case with due diligence," Nicol said. "We had no issues with health in trying to address the problem."
Nicol said the district sent out public notices and did all it could to protect people from contamination.
The District of Coldstream and the farm where the manure originated plead guilty to charges stemming from the incident, and were fined $18,000.
Similar fines are expected for the Regional District of the North Okanagan.
Also on HuffPost