U.S. Environmental Protection Agency: Ground Water & Drinking Water
water.epa.gov/drink/index.cfm

U.S. Environmental Protection Agency: Arsenic in Drinking Water
www.epa.gov/safewater/arsenic/index.html

Arizona Department of Environmental Quality: Water Quality Division
www.azdeq.gov/environ/water/index.html

Arizona Department of Health Services: Environmental Water Microbiology
www.azdhs.gov/lab/micro/envwater.htm

Maricopa County Environmental Services Dept.: Water Quality
http://www.maricopa.gov/EnvSvc/WaterWaste/DrinkingWater/DrinkingWater.aspx

Centers for Disease Control: Water Quality
www.cdc.gov/health/water.htm