Residential
A backflow prevention assembly is required on lawn-irrigation systems and may be required for certain residential businesses.
Protecting the water system
Backflow prevention
Requirements for irrigation systems, certain businesses, new construction, and annual assembly testing.
Commercial
A backflow prevention assembly is required on lawn-irrigation systems and for certain types of businesses.
Annual testing
All backflow assemblies must be tested annually, as required by Public Law 99-399 and 10 CSR 60-11.010.
Submitting test information
If you are moving into new construction, send the District a copy of the initial Backflow Prevention Assembly Test Data.
After installation, every assembly must be tested annually. Provide the District with a copy of the completed test data each year.
View DNR backflow guidance (PDF)
Questions about your property?
Call the office at (636) 467-6868 before installing or modifying a system.