Backflow Prevention

Backflow is the undesired reversal of the flow of liquids - such as irrigation water - into the drinking water system.

The two forms of backflow are:
  • Back siphon - the action of flow reversal caused by a reduction in line pressure
  • Back pressure - the increase of water pressure caused by elevation or mechanical pumping
back flow picture
The installation of a backflow preventer will protect drinking water systems from possible contamination.

If you have questions, would like more information regarding your irrigation system and backflow protection, or if you just need some help, contact us before doing any work at 415-945-1488.
Backflow Parts Vendors
List of Certified Testers

List of Approved Assemblies

MMWD Irrigation Backflow Brochure

Security and Freeze Protection Enclosure Options

Information for the Board on Cross Connection/Backflow Control Program

Resources and Links

American Water Works Association

American Backflow Prevention Association

Backflow Video Resources:

University of Southern California