Chlorine disinfection destroys Giardia, bacteria and viruses that may be present. Because our water is naturally soft, minerals are added to inhibit corrosion in your plumbing. Fluoride is added to help prevent tooth decay. This new facility began full production in December 2000, adding ozone disinfection and filtration to the current treatment routine. Filtration removes turbidity and naturally occurring organic matter that can combine with chlorine to form disinfection by-products.
Filtration also improves the reliability of the water supply.
Ozone disinfection is very effective at killing Cryptosporidium . It will improve public health protection by disinfecting Cryptosporidium and improve the taste and odor that can occur on this supply. The facility is being developed in part to comply with an Agreed Order between Seattle Public Utilities and the Washington Department of Health. The Agreed Order was executed after one of the eleven criteria to remain unfiltered was exceeded in 1992. There was no public health risk associated with this event, as treatment and monitoring occurred as required.