The author explains how drinking water guidelines are developed in Canada. The methods for derivation of the maximum acceptable concentration (MAC) are described. The Federal-Provincial Subcommittee on Drinking Water has a list of priorities for development of new guidelines or review of existing guidelines. This priority list which is given as a table accompanying the article, is revised annually and usually represents at least three years of work. The mechanism for public comment on proposed guidelines has been by a one-year comment period on proposed new guidelines after their publication by Health and Welfare Canada. It has always been the policy that guidelines can be challenged at any time, especially when new evidence comes to light. The author also touches on the topics of microbiological characteristics of water and whether current microbiological indicators are sufficient to guard against waterborne gastrointestinal disease. There are no plans to bring forward a drinking water safety act, which would cover mandatory regulations for water quality in the following areas: water treatment chemicals, materials in contact with water, and point of use devices.