The purpose of a rain sensor is to conserve water by interrupting already scheduled watering cycles after adequate rainfall. they not only conserve water, but help you to save money on your water bill.
Rain sensors contain a small disc that swells when it detects rainfall. When it reaches a set level ( the St. John’s River Water Management District recommends the level should be set for one-quarter of an inch), it depresses an electrical contact switch which interrupts the electrical signal going to the irrigation valves. This keeps the valves from turning on, or shuts them off if they are already running.
Although a rain sensor is a very important tool for us to utilize, you should remember that you still must actively manage your irrigation system.
We recommend you turn your irrigation system off after rainfall events, and wait for your lawn to “tell” you when it needs to be irrigated before turning your system back on. Signs your lawn needs irrigation include the following:
grass blades folding closed,
lingering footprints or mower tracks
or the first few inches of soil feeling dry.
The Southwest Florida Water Management District has provided an excellent video for how to test your rain sensor.