Moving to Seattle in Pacific Northwest & Alaska: Cooking & Baking Posted August 5, 2006 At certain times of the year, they have to add more or less chlorine due to the amount of organic material in the watersources. Those of you in Seattle have read of the recent algae blooms such as red tide. In warm weather such as this, algae and other micro-organisms flourish in the water supply and must be eliminated by chlorine and other means of disinfecting the water supply. Seattle, and other water supply entities, prefer to keep the use of chlorine to a minimum, using other methods instead. But when you have a big bolus of water disinfecting to do, chlorine is easy, cheap and effective. It is often used as a supplemental method for situations such as algae bloom. The alternative is risking killing your customers, as occurred in Milwaukee in 1993, when the water supply was contaminated by cryptosporidium, resulting in over 100 deaths and 400,000 cases of serious illnesses. Pouring the water into a glass or pitcher and allowing it to outgas for an hour or two will usually reduce or eliminate the chlorine odor and taste.