Backflow Laws: Missouri
Missouri Backflow Prevention Laws, Regulations, and Compliance Requirements
Missouri's backflow prevention requirements are established under 10 CSR 60-11.010, administered by the Missouri Department of Natural Resources (MoDNR). MoDNR certifies backflow prevention testers and maintains the state certified tester database. Missouri requires annual testing, with test results filed with both the water district and the state MoDNR. The MoDNR Backflow Prevention Assembly Test Data and Maintenance Report form is the required test documentation. This guide covers MoDNR's regulatory framework, Missouri American Water's statewide program, and major utilities in Kansas City, St. Louis, and Springfield.
Missouri State Regulatory Framework
Missouri’s cross-connection control and backflow prevention requirements are established in Missouri Code of State Regulations 10 CSR 60-11.010 — the Missouri Department of Natural Resources (MoDNR) Backflow Prevention Rule. MoDNR holds EPA primacy under the federal Safe Drinking Water Act. The rule applies to all community water systems and allows the supplier of water to require customer facilities identified as actual or potential backflow hazards to provide necessary protection to prevent contaminants from entering the public water system through an unprotected cross-connection.
Missouri’s rule exempts residential facilities unless a cross-connection is specifically identified. However, the most common residential cross-connections — in-ground lawn sprinkler systems, swimming pools, hot tubs, and fire sprinkler systems — do require backflow prevention when identified. Businesses connected to community water systems must install backflow prevention per 10 CSR 60-11.010 if a potential or actual connection exists between a contamination source and the water supply.
Missouri recognizes three types of backflow prevention assemblies: air gaps, reduced pressure principle assemblies (RPZ), and double check valve assemblies. All recognized assemblies require periodic maintenance and annual testing. MoDNR requires that test results be filed with both the water utility AND with MoDNR — dual filing is a distinctive feature of Missouri’s program.
MoDNR Certified Backflow Prevention Tester Certification
Missouri DNR certifies backflow prevention testers. Testing must be performed by a Missouri DNR-certified backflow prevention tester. MoDNR maintains a list of certified testers on its website, and only testers from this list with current certifications are accepted by Missouri water utilities. Missouri American Water explicitly states: ‘Only testers from [the MDNR] website with current certifications are accepted.’
The MoDNR Backflow Prevention Assembly Test Data and Maintenance Report form is the standard test documentation for Missouri. Both the water district and the MoDNR must receive copies of completed test reports. Failed assemblies must be repaired or replaced no later than 30 days from discovery of the defect, and the device must not be bypassed, made inoperative, removed, or otherwise made ineffective without specific written authorization by the district.
Missouri's Dual Filing Requirement
Missouri requires that backflow prevention assembly test results be submitted to BOTH the water district AND the Missouri Department of Natural Resources. Many states require filing only with the local water utility. Missouri’s dual filing creates a state-level database of all assembly tests, enabling MoDNR to track compliance statewide. Testers and property owners must ensure both submissions are completed — filing only with the water district does not satisfy the full Missouri compliance requirement.
Major Water Purveyors in Missouri
Missouri American Water
Missouri American Water is the largest investor-owned water utility in Missouri, serving communities across the state. Missouri American Water’s cross-connection control program aligns with MoDNR 10 CSR 60-11.010. Missouri American Water explicitly requires that only testers appearing on the MoDNR certified tester list with current certifications perform testing in their service areas. Test results must be submitted per Missouri American Water’s filing instructions, which include the MDNR test form.
Kansas City Water Services
Kansas City Water Services serves Missouri’s largest city and surrounding areas. Annual testing is required for all covered commercial and industrial connections. Kansas City’s cross-connection control program follows MoDNR regulations with its own specific filing procedures and deadlines. Test results must reach both Kansas City Water Services and MoDNR within 30 days of the test date.
Metropolitan Sewer District (MSD) and St. Louis Area
The St. Louis metropolitan area’s water is supplied by Missouri American Water (St. Louis county communities) and the City of St. Louis Water Division. Both operate cross-connection programs under MoDNR 10 CSR 60-11.010. The large number of commercial, industrial, and healthcare facilities in the St. Louis metro creates a substantial cross-connection compliance environment. MoDNR-certified testers are required for all testing.
Springfield City Utilities
Springfield City Utilities serves the Springfield metropolitan area in southwest Missouri. City Utilities operates a cross-connection control program requiring annual testing by MoDNR-certified testers. Test reports are submitted to City Utilities and MoDNR per state requirements. Irrigation systems, fire protection systems, boilers, and industrial processes all require backflow prevention.
Jackson County PWSD #12 and Other Water Districts
Jackson County Public Water Supply District #12 serves portions of Kansas City’s suburbs. PWSD #12 mails Backflow Packets annually on April 1st to customers with irrigation systems, requiring completed inspection forms by May 31st. The district provides a list of MoDNR-certified testers and requires that test results be forwarded to the district for their files as well as to MoDNR. Newly installed irrigation systems also require backflow inspection regardless of installation date. The district’s 30-day repair window applies to all failed or defective assemblies.
Missouri's April/May Irrigation Filing Calendar
Several Missouri water districts, including Jackson County PWSD #12, have established spring-specific annual deadlines for irrigation system backflow testing — typically mailing compliance packets on April 1st with results due by May 31st. This compressed spring calendar means property owners with irrigation systems must schedule testing early in the season to avoid deadline pressure. Waiting until late May to schedule in a busy spring market may result in testing being unavailable before the deadline.
Property Owner Compliance Summary for Missouri
MoDNR-certified tester: Testing must be performed by a Missouri DNR-certified backflow prevention tester appearing on the current MoDNR certified tester list.
Dual filing: Test results must be submitted to BOTH the water district AND the Missouri Department of Natural Resources.
Annual testing: Required for all RPZ, DCVA, and air gap installations. 30-day repair window for failures.
MoDNR form: Use the MoDNR Backflow Prevention Assembly Test Data and Maintenance Report form as the standard documentation.
No unauthorized bypass: Assemblies must not be bypassed or made inoperative without specific written authorization from the district.
Find a Certified Backflow Tester in Missouri
Find MoDNR-certified testers at getyourbackflowtested.com/backflow-testing-near-me/missouri-backflow-testing — covering Kansas City, St. Louis, Springfield, Jefferson City, and all major Missouri markets. Verify certification status through the MoDNR certified tester list.
Missouri Regulatory Reference Links
| Resource / Agency | URL / Link Target |
|---|---|
MoDNR — Backflow Prevention | |
MoDNR — Backflow Prevention Basics (PUB0393) | |
MoDNR — Cross Connection Customer Guide (PUB2940) | |
10 CSR 60-11.010 — Missouri Backflow Prevention Rule | |
Missouri American Water — Cross Connection & Backflow Prevention | |
Jackson County PWSD #12 — Backflow Information |