Helpful Links...

Skagit PUD #1................................................................http://skagitpud.org/
Department of Health Drinking Water............................http://www.doh.wa.gov/CommunityandEnvironment/DrinkingWater.aspx
EPA................................................................................http://water.epa.gov/drink/
USC Backflow Introduction............................................http://www.usc.edu/dept/fccchr/intro.html
Backflow Case Studies..................................................http://www.wrcmanagement.com/Case_Studies.html