Backflow Testing for Irrigation Systems

Backflow testing requirements are mandated by the Environmental Protection Agency (EPA), the Safe Drinking Water Act (SDWA) and the Missouri Department of Natural Resources (MDNR), along with City Ordinance # 1592.

Backflow devices are required to be installed on all irrigation systems, fire sprinkler systems and commercial service lines and to be tested annually by a State of Missouri certified tester. Annual backflow test reports are due to the City of O’Fallon Utility Billing Department by June 1st of each year. If the report is not sent to the City of O’Fallon by June 1, then a late fee of $30.00 will be assessed. Reports that are not received by July 1st will be subject to disconnection of water service and additional fees.

For a list of Approved Backflow Prevention Assembly Testers, please visit Missouri Department of Natural Resources website at the following link:

Please submit backflow test report(s) to:

City of O’Fallon Utility Services
100 N. Main St.
O’Fallon, MO 63366

Reports may also be faxed to 636-379-5618 or sent by email to This email address is being protected from spambots. You need JavaScript enabled to view it.