City of Wentzville Water Division: backflow testing rules

Who must test

• All lawn irrigation systems, fire sprinkler systems and commercial service lines must have a backflow prevention device tested annually by a state of Missouri certified tester. Source.
• Instead of testing, a lawn irrigation system can be deactivated by removing its backflow device, with a deactivation inspection scheduled before June 1. Source.

Notices and deadlines

• Annual backflow test reports are due by June 1. Source.

How the report is filed

• Test results can be emailed to Backflow.Test@wentzvillemo.gov, delivered in person, or mailed to Attn: Backflow Reporting; emailed reports get a confirmation receipt. Source.

Tester registration

• Tests must be by a state of Missouri certified tester; the city points to the Missouri Department of Natural Resources website for the list of certified testers. Source.

Fees

• Wentzville charges a water backflow filing fee on the customer's water account: $14 if received before June 1, $18 from June 5 through July 1, and $38 after July 5. The receipt date, not the test date, sets the fee. Source.
• All irrigation systems must get a permit before installation, and a backflow permit registration is mandatory. Source.

If a test is missed

• Reports received after July 5 are charged a $38 late filing fee; each report is stamped with the date received. Source.

Read October 6, 2026. Program page: wentzvillemo.gov.

Certified backflow testers near Wentzville

All certified testers near Wentzville · Missouri roster