If you are on a private water and sewage system, you should be aware that high water levels may contaminate your drinking water. For example, pooling of water around wells may cause well water contamination.

If you live in a flooded area, you should boil water to be used for drinking, washing uncooked fruit and vegetables, preparing baby formula, making coffee, juice and ice cubes, and brushing teeth. Water should be brought to a  boil and kept at a full rolling boil for one minute. You should continue this until you have your water tested.
 

A Homeowners' Checklist for After the Flood from Canada Mortgage and Housing Corporation. 

www.cmhc.ca/en/burema/gesein/abhose/abhose_ce07.ca