REGINA -- Residents in Coronach are being warned to not use tap water after a break-in at the water treatment plant.

According to the Water Security Agency, an unknown substance may have been added to the water.

A notice sent to residents said they should only use bottled water and they should not try to treat the water themselves as boiling or filtering the water will not make it safe.

The Water Security Agency said there now has to be a complete flush of the system due to the incident.

The advisory went into effect at 10:25 a.m. on Monday and will be lifted when it is determined the water supply is safe.