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Department of Health Services

Environmental Health and Safety

Well Water Treatment for Non-Bacterial Contamination

This guide presents options available to treat a water well for non-bacterial contaminants. Treatment devices are generally of three types:

  • Point of use, (faucets)
  • Point of entry, (on main water line entering the house)
  • Well head (at the well)

Some contaminants can be adequately treated at indoor taps. Other contaminants, however, may volatilize and harmful vapors might be released, such as when using showers or washing machines. These contaminants are impractical for point-of-use filters. They would be better treated at the point of entry or the wellhead. Wellhead treatment technologies are currently unproven, experimental, or impractical.

Sonoma County Environmental Health & Safety recommends that you talk with a water treatment professional about your specific situation to assure that the system you are considering will work for your needs.

To ensure that any treatment device considered is certified as to its effectiveness by the State of California visit the State Water Resources Control Board website:

List of Registered Residential Water Treatment Devices

Contaminant Activated Alumina Filters Activated Carbon Filters Mechanical Filtration Oxidizing Filters Ozonation Reverse Osmosis
Arsenic x x
Asbestos x x
Benzene x x
Chlorine x
Color x x x
Flouride x x
Hydrogen Sulfide x x
lnorganics, minerals (some) x
Iron/Manganese- dissolved x
Iron/Manganese- insoluble x x
Lead x
Mercury x x
Nitrate x
Odor and taste x x x x
Pesticides (some) x x x
Salt x
Sand, silt, clay (turbidity) x
Uranium x
Volatile organic compounds x x

Treatment Technologies

If water quality tests show a chemical above the maximum contaminant level (MCL), it is a good idea to use an alternate drinking water source and look into ways to fix the problem. Boiling your water or disinfecting with chlorine does not remove many of the commonly found chemicals or naturally occurring substances.

Not all water treatment systems work for every substance or water type. Once installed most systems require routine maintenance to continue performing properly. It is strongly recommended that you talk with a water treatment professional about your specific situation to ensure the system you are considering will work for your needs. 

Information about water treatment devices for residential use (State Water Resources Control Board)

Connecting to Public Water Systems

Public water systems use water treatment and regular monitoring to protect consumers from such substances.  If well owners have the ability to connect to a public water system (e.g. city water or water district) it may be beneficial as an alternative to the maintenance and testing of your well.

Community Water Center address lookup tool: Where does my drinking water come from?