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Florida Water Star Technical Manual

Irrigation system criteria

Operation and scheduling

Evapotranspiration (ET) controllers


An ET controller uses weather-based information to determine when the irrigation system should operate. This controller uses three types of information:

  1. Off-site weather measurement transmitted through wireless communication
  2. Historical ET
  3. On-site weather measurement

The irrigation schedule is programmed by using a formula that calculates the water requirement, which is based on either local, regional or historical information.

Evapotranspiration controller

An ET controller.

Evapotranspiration controller

An on-site ET sensor.

Evapotranspiration controller

Another on-site ET sensor.

Requirements and certification

ET, smart, or weather-based controller is correctly installed, programmed, and functioning.





15 points


An on-site weather monitoring device must be installed in a location that is unobstructed from normal rainfall and which is representative of the overall site conditions.

The Florida Water Star Inspector must confirm the following:

  1. Installation of controller and weather station (if applicable)
  2. Wiring to the controller
  3. Weather data service (if applicable)
  4. That the controllers bypass function is activated
Program tip

Smart Water Application Technology (SWAT) devices are capable of increasing scheduling efficiency, resulting in significant water savings. However, correct installation of these devices requires diligent planning and implementation of a number of best practices. Designers and installers must ensure that any type of SWAT device is able to provide the greatest water savings possible.

St. Johns River Water Management District
4049 Reid Street, Palatka, FL 32177