The City requires that new water services install a backflow prevention device approved by the State Water Board. Located just after the meter, the device protects the public water supply in the mains from potential contamination by non-potable "used" water drawn in from the customer side. A working backflow prevention device ensures that no waste liquids, industrial fluids, fertilizers, pesticides, or other contaminants reach the public drinking water supply. All devices must be tested annually and immediately repaired if necessary. For more information, contact the Cross Connection Control Program Coordinator at 707-257-9912.