Drinking Water Quality Standards & Definitions

Standards and monitoring requirements to safeguard water quality are set by United States Environmental Protection Agency as established in the U.S. Safe Drinking Water Act of 1974 and amendments. In California, the Department of Health Services is the responsible agency which can and often does, set more stringent standards then the federal government. There are two types of drinking water standards:

• Primary Standards which are set based on research, data collection and analysis by health experts to protect public health.
• Secondary Standards which are set based on aesthetic qualities of water for example color, taste, odor, which may influence customer’s acceptance of water.

The following definitions will help you better understand the Annual Water Quality test results:

• PHG – Public Health Goal: The level of a contaminate in drinking water below which there is no known or expected risk to health. PHGs are set by the California Environmental Protection Agency.
• MCLG – Maximum Contaminate Level Goal: The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs are set by the U.S.Environmental Protection Agency.
• MCL – Maximum Contaminate Level: The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the PHGs amd MCLGs
• DLR – Detection Limit Reported: The method chosen for determination of a constituent must comply with a minimum detection set by the Department of Health Services.
• *: MCLGs have not been finalized.
• NS – No Standard: At the present time, this parameter/constituent is monitored, but a MCL has not been set.
• ND – Not Detected: This means that the parameter/constituent was monitored, but was not found at or above the DLR.
• Turbidity: This is a measure of fine particles in water.
• <: This means less than.
• mg/l – milligram per liter: This is equivalent to:
  • 1 minute in 2 years
  • 1 inch in 16 miles
  • 1 cent in $10,000
  • 1 black marble in 1,000,000 white marbles

Stockton East Water District wholesales treated surface water to the City of Stockton, California Water Service Company and San Joaquin County. If you live in the Stockton urban area, you can contact your water provider for water quality information reflecting your service area.

City of Stockton
(209) 937-8295

California Water Service Company
(209) 547-7900

San Joaquin County
(209) 468-3090