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Water Backflow Prevention Devices & Testing Requirements




If you have a lawn irrigation system at your home or business, you are required by the Missouri Department of Natural Resources to:

  1. Have an approved backflow prevention device. St. Peters Code 705.320 requires that all irrigation systems have a reduced pressure principle backflow prevention device.
  2. Have the device tested annually.


Backflow prevention devices must be tested by a state certified backflow prevention tester and the test reports submitted to your water supplier by the anniversary date established by the supplier. For those residents who receive water from the City of St. Peters, that anniversary date is June 1. Remind your irrigation service contractor to send a copy of the test report to your water supplier. This test is required whether or not you plan to use your irrigation system. St. Peters ordinance also requires that residents maintain records of their devices from purchase to retirement. If a device is removed from service, proof of proper disconnection and cap off shall be provided.


A $10 administrative fee is required for each backflow prevention device test report submitted.


Backflow prevention devices help protect you and our community by preventing potentially contaminated water from coming back through the irrigation system and into your home or the public water supply. Many commercial businesses must also have backflow devices on other water supply systems such as boilers, car washes, medical facilities and fire sprinkler systems to name a few.


If you have any questions regarding backflow protection at your business or residence, call the City of St. Peters at 636-477-6600, ext. 1317. You can also find more information online at




Search the Missouri Department of Natural Resources' list of state-certified testers.