A boil water notice has been issued for people within the OK Falls Irrigation District.
According to district spokesperson, Judy Morris, the E. coli bacteria has been discovered in the water system.
"We just did our water sample on Tuesday and got contacted by our lab this morning," says Morris.
"We are in the process of flushing all the water mains then we will be doing some more testing."
Morris says it's too early to tell when the notice will be lifted.
The notice affects people mostly in the townsite of Okanagan Falls.
Morris says all drinking water and water for preparing food, brushing teeth and making ice should be brought to a rolling boil for one minute then let cool in the fridge before using.
This is the first time in about 10 years E. coli has been discovered in the town's water supply.
Morris says they don't know yet how the bacteria made it to the water supply.
That is still under investigation.