Backflow Prevention

As part of Coastside County Water District’s commitment to delivering safe, reliable, high quality water to our customers, the District maintains an effective Cross Connection Control (Backflow Prevention) Program. This program is implemented in accordance with the requirements of the California Administrative Code Title 17, and was implemented by the District in 2001 and revised in 2013. See Ordinance No. 2013-01

Installation of Approved Backflow Prevention Devices

If you are a Coastside County Water District customer and your water service meets the requirements for the installation of a backflow prevention device, the District wants to make the process as easy as possible for you. The following information should assist you with the process:

Where are the devices installed?
The device is installed on the customer’s water service line immediately after the water meter.
Who can install the devices?
A licensed contractor, plumber, backflow professional, or the property owner can install the device.
Backflow Prevention Device Installation/Testing Information
Compliance Requirements
After the initial installation, inspection, and testing of the backflow prevention device, the customer must:
- Maintain the backflow prevention device
- Submit annual test results to Coastside County Water District. You will receive a reminder, including a test report form and current list of certified backflow prevention device testers on an annual basis from Coastside County Water District.
Contact Information
- For questions regarding requirements please call (650) 276-0799
- Email address: backflow@coastsidewater.org

Requirements for Backflow Prevention Assemblies

Water and Fire Service Connections – A backflow prevention assembly must be installed on all non-residential water service connections and on residential water service connections that have an auxiliary water supply, a cross connection, a storage tank or other risk of backflow contamination.

Water service connections that serve single-family, duplex, and triplex residential properties with structures less than three stories tall and without auxiliary water supply, or additional water service connections are typically exempt from backflow prevention assembly requirements.

What is Backflow?

Backflow means the reverse flow of water or any other fluid or substance, or any combination, or any mixture thereof, from the customer’s system into the District’s water distribution system.

What is a Cross Connection?

Cross Connection means any connection between the District’s water distribution system and an auxiliary water supply, a pipe or piping system, plumbing fixture, appliance, container, receptacle, vessel or other devices that may allow for contaminated water, fluids, or other substance, other than the water supplied by the District, to enter any part of the District’s water distribution system.