Public Drinking Water Branch

Backflow Prevention

What is backflow?

Backflow, or the reverse flow of contaminated water into a potable water distribution system, is caused by backsiphonage or backpressure.

Recommended Actions

How to become a certified backflow tester
Missouri Backflow Prevention Regulations
Basics of Missouri Backflow Regulations -- PUB393
Backflow Prevention Frequently Asked Questions -- PUB 2158
Missouri Backflow Prevention -- PUB2016
Approved backflow assembly list

Backflow Prevention Assembly Testers

Note icon. The department has changed all fill-in forms to PDF fill-in. You will be able to save and reuse these PDF forms. However, you will need Adobe Acrobat Reader 7 or higher to save the PDF fill-in form. Also, at this time the department does not accept digital signatures. If your Acrobat Reader prompts you to use one, we ask that you don't.

Backflow Assembly Test form 780-0804

American Society of Sanitary Engineering
American Backflow Prevention Association Tester Certification Information
Foundation for Cross-Connection Control and Hydraulic Research
U.S. Environmental Protection Agency Cross-Connection Manual
Drinking Water Security
EPA Backflow Prevention Devices