This indicator measures the percent of dwelling-days that the RMOW delivered quality drinking water, reporting a score out of 100%. A perfect score of 100% means that for each day of the year quality water was delivered to all of Whistler’s 15,000+ dwellings. An imperfect score of less than 100% means that at some point during the year diminished water quality lead to a boil water advisory that impacted at least one dwelling for a period of time. Scoring scales based on the duration boil water incidents and the number of residential and commercial dwellings impacted. Boil water advisories are issued when tested sample results do not meet Canadian Drinking Water Guidelines and as a precautionary measure when there is some cause for concern, such as a minor break somewhere in the water delivery system.