State rules
Missouri
The Missouri Department of Natural Resources certifies backflow prevention assembly testers under 10 CSR 60-11.030. The Department’s backflow page says certification is obtained by passing both a written examination and a hands-on performance examination provided by the American Backflow Prevention Association or the American Society of Sanitary Engineering. The exams include testing and diagnosis of the double check valve, the pressure vacuum breaker, and the reduced-pressure principle assembly, and they are conducted under an independent proctor. The rule says the exam must include questions specific to Missouri backflow rules, and ABPA or ASSE must notify the Department that the person passed. Certification is valid for three years.
Checked against official sources on October 11, 2026. Rules and links change; confirm with the office listed before you act.
- Drinking-water agency
- The Missouri Department of Natural Resources certifies backflow prevention assembly testers.
- Who may test an assembly
- A certified backflow prevention assembly tester who passed ABPA or ASSE written and performance exams, including Missouri-rule questions, and whose passage was reported to the Department.
- Official program page
- Official page →
- Tester lookup
- Official page →
The rule applies to everyone seeking certification or recertification. A certified tester inspects, tests, and reports on assemblies under 10 CSR 60-11.010. False information is grounds for denying or revoking certification. Reciprocity is limited: a tester listed with ABPA or ASSE may be certified when ABPA or ASSE notifies the Department that the tester completed an examination on Missouri backflow rules. The Department’s publication PUB2016 says course instructors may not test their own students, and that the written exams contain about 100 questions. It also says the Department prepares an annual schedule of dates and locations on request.
State regulations require assemblies at community water systems to be approved by the USC Foundation for Cross-Connection Control and Hydraulic Research or by ASSE. Missouri allows only double check valve assemblies, reduced-pressure principle assemblies, or an approved air gap as containment devices. Other devices on a broader list are not containment devices under 10 CSR 60-11.010 and 11.030. PUB2016 says all air gaps, reduced-pressure assemblies, and double-check assemblies shall be inspected when installed and at least annually by a certified tester. The water supplier must notify the Department within 48 hours of a backflow incident that caused contamination.
The certified-tester page says public water systems use assemblies to keep contaminated water out of the potable system, and that state regulations require inspection and testing by certified assembly testers. The page states the list is not an endorsement. The branch telephone on that page is 573-751-5331. Missouri Revised Statutes section 650.295 says a person certified by the Department is eligible to be registered or licensed by a political subdivision to test and repair within that subdivision while the state certification is maintained, and that a subdivision may set additional testing standards.
Official resources in Missouri
Explains ABPA and ASSE exams and which assemblies count as containment devices.
Department list page for certified testers, with the public drinking water branch telephone.
Certification, three-year term, Missouri-specific exam questions, and reciprocity.
Key facts for Missouri
- Certification requires written and hands-on exams from ABPA or ASSE, including Missouri-rule questions.
- ABPA or ASSE must notify the Department that the tester passed.
- Certification is valid for three years.
- Containment devices are limited to double check valve assemblies, reduced-pressure principle assemblies, or an approved air gap.
- Air gaps and those assemblies are inspected at installation and at least annually by a certified tester.
- A Department-certified tester is eligible for local registration while the state certification remains in effect.
What to do next
- Ask for the Missouri certification, not only an ABPA or ASSE card from another state, unless reciprocity notice to the Department is complete.
- Use the Department’s certified-tester list and remember the page says it is not an endorsement.
- Ask whether the device is being used as containment; pressure vacuum breakers are in the exam but are not listed as containment devices.
- A city may add testing standards on top of the state certification.
Looking for your city or county in Missouri?
We haven't found official program-level pages for Missouri we can verify yet, so we don't show local numbers here rather than guess. Here's what to use instead, in order:
- General Start with the statewide information above. It applies across Missouri, but cities and counties can add their own steps, fees or deadlines.
- Call to confirm Ask the official office. They have the current local rule, fee and form.Missouri DNR Public Drinking Water Branch
Website →Phone: (573) 751-5331 (as listed on that page, checked Oct 4, 2026)Your city or county office: Local governments →Not sure who handles it locally? USAGov's free help line, 1-844-872-4681, or the Missouri page on USA.gov can point you to the right office. - Know the current info? Tell us and include a link to the official page. We check every tip before it goes up.
Helpful guides
- What a backflow test is
- Who is allowed to test a backflow assembly
- Why utilities require annual backflow testing
- Tester and cross-connection specialist