http://www.bbc.com/earth/story/20170504-there-are-diseases-hidden-in-ice-and-they-are-waking-up
Guidelines for Canadian Drinking Water
Guidelines for Canadian Drinking Water – Federal Government
Reading through the guidelines you will find that many contaminates come through not only natural occurring water supplies, but also contamination can occur through post municipal systems as well. A good read to understand the water you drink. It will also help you understand how the government is dealing with our water.