Backflow testing assures that contaminated water does not back up from a home or business into the potable water supply, either accidentally or intentionally. Missouri requires periodic backflow tests, depending on the county or municipality. The state requires all backflow testers to be certified by either the American Backflow Prevention Association or the American Society of Sanitation Engineering . Both organizations have specific requirements for tester certification, requiring study courses and examination.

Complete a training course in backflow testing. The State of Missouri Department of Natural Resources has a list of authorized union and non-union training facilities in the state at their website, starting at page three of the first resource.

Complete the written and performance examinations given by the ABPA or the ASSE tester certification programs. The tests have specific questions for Missouri. See the ABBA or ASSE websites for test schedules, or contact the training facility where you studied.

Ensure that ABPA or ASSE notifies Missouri that you passed the written and performance examinations to be certified. The state claims no responsibility to get your results. Your certification becomes valid when the state receives the information.

Renew your certification every three years with the ABPA or the ASSE via their retesting programs. Again, ensure that the ABPA or ASSE contacts Missouri to report your successful re-certification.