Ever since the first solid state irrigation controller was invented back in 1976 by John M. Buckner, irrigation technology has progressed tremendously. We now have irrigation programmers that are controlled by weather stations and some that even e-mail or text you when a problem arises.

But what all these controllers have in common – whether they're residential or commercial systems – are rain sensors. Although rain has been scarce, it is likely to return one day and when it does, a rain sensor for your irrigation system will come in very handy.

Mounted in an unobstructed rainfall area outdoors, a rain sensor is wired to your system's controller and designed to override the cycle program, suspending watering during and after adequate rainfall has been received. The controller resumes its regular schedule once the disk in the sensor dries out. The rain sensor should be set to shut the system off once a quarter-inch of rainfall has occurred.

Some of the newest technologies in rain sensors are the wireless types. These sensors communicate by sending a signal to a module that is connected to your controller. There is even a rain sensor available that has a rain delay program, allowing you to suspend your watering schedule after it rains up to four days.

This equipment saves money and water by not watering when it rains. Rain sensors can be installed by homeowners and irrigation professionals and are available wherever irrigation supplies are sold.

Adolph M. Garcia is a senior technical field investigator for San Antonio Water System.