Protecting the Public Water Supply is Everyone's Responsibility

The City of Frisco takes pride in the water we provide, and we strive for uninterrupted service. The water entering the distribution system is a protected, potable water meeting or exceeding all State and Federal standards. Once the potable water enters the point of service, it is the responsibility of the property owner to ensure backflow does not occur.

Backflow Testers

To provide the best program possible, the City of Frisco partnered with Backflow Solutions, Inc. or BSI Online, the nation's leading backflow data management firm. BSI is fully devoted to helping public water systems with the development, implementation and maintenance of cross-connection control programs. The backflow test fee (administered through BSI) is $40 per device. For questions or to obtain a list of registered Backflow Prevention Assembly Testers contact: 

About Backflow

Backflow is the undesirable reversal of the flow of water in a potable water distribution system as a result of a cross connection. In other words, backflow is water flow going in the wrong direction. There are two types of backflow:

  • Backpressure - This occurs when water generated pressure from a private service exceeds the water pressure provided by the city's water system. Causes for increased pressure from a private system may include a pump, elevated tank, boiler, or other condition.
  • Backsiphonage - This occurs when backflow is caused by negative or reduced pressure in the supply piping.

Backflow Prevention Assembly

A backflow prevention assembly is a mechanical device used to prevent backflow. The check valves are designed to close if the water flow is reversed to prevent backflow. The assemblies have test ports for periodic testing. The type of assembly required depends on the type of potential hazard found after an inspection by the Public Works Backflow Inspector.


All backflow prevention assemblies require a plumbing permit from the City of Frisco Public Works Department before installation. A licensed plumber, registered with the City of Frisco, may install the required backflow assemblies. The backflow assembly on an irrigation system may be installed by a licensed irrigator who is registered with the City of Frisco.


Approved backflow prevention assemblies must be installed to comply with City of Frisco Ordinance Number 2022-04-12 (PDF) as well as state and federal environmental laws. Certain backflow prevention assemblies with test ports must be tested upon installation and thereafter annually by a licensed backflow tester. A fee per assembly, as stated in the fee schedule, will be charged by the City of Frisco for annual inspections. This fee is in addition to any testing charges by the backflow tester.