The answer to 'how to maintain backflow preventer' is to regularly inspect, test, and clean the device to ensure it is functioning properly and preventing backflow. Backflow preventers are critical safety devices that stop contaminated water from flowing back into the clean water supply, so proper maintenance is essential.
You should have a certified backflow tester inspect and test your backflow preventer at least once per year, or more frequently if required by local plumbing codes. The technician will check for proper operation, leaks, and any necessary repairs or replacements. Between annual tests, you can perform basic maintenance by visually inspecting the device for any cracks or damage, and cleaning the inlet and outlet screens to remove debris.