Unregulated Drinking Water Supplies

General Information on Private Water Supplies

Unlike regulated water supplies, people who obtain their drinking water from an unregulated water supply, such as a privately drilled well, a shallow dug well, a stream, a spring, a pond, a lake, or a cistern are responsible for determining the safety of the water themselves. The quality of a private water supply can be variable. Some have adequate treatment and are well managed, but others present a health risk due to the water quality and/or lack of proper treatment. If you own or use a private drinking water supply, it is important that you are aware of the quality of the supply, the risks associated with that supply, and the suggested forms of treatment of that supply if necessary. There are things a user of a private water supply can do to protect themselves, including but not limited to:

• Make sure the source is protected from contamination from grazing animals or material washing down from upstream
• Installing and maintaining appropriate treatment that can treat water to a consistently satisfactory quality
• Make sure the water is properly disinfected prior to use, if necessary
• Make sure that water is stored and distributed in a way that prevents contamination prior to consumption

Information on Private Groundwater Supplies

The following websites contain information on properly sited and drilled wells:

• California Waterboards — Groundwater data and online tools
• California Waterboards — Water Quality in Private Domestic Wells
• California Waterboards — A Guide for Private Domestic Well Owners
• US EPA — Private Drinking Water Wells
• Centers for Disease Control — Private Groundwater Wells
• California Waterboards — California Harmful Algal Blooms (HABs)
• Information on how to test your drinking water quality

Information on Private Surface Water Supplies

Water from shallow dug wells, steams, springs, ponds, lakes, and/or cisterns are considered to be surface water. Unlike groundwater, surface water can contain contaminants and pathogens that have been picked up from the surface of the ground and may make people sick. See these links for more information on surface water:

• Wikipedia—Surface Water
• New York State Health Department — Concerns About Surface Water as a Drinking Water Source
• California Waterboards — Data and Databases - Surface Water
• United States Geologic Survey — Surface Water Information
• California Waterboards — California Harmful Algal Blooms (HABs)
• Information on how to test your drinking water quality