The Florida Climate Center in Tallahassee reported that our area saw more than 8 inches above normal rainfall in June and July.


The Florida Climate Center in Tallahassee reported that our area saw more than 8 inches above normal rainfall in June and July.



More than 700 storms were recorded statewide, 200 of which were in the first week of July. Flooding meant washed out roads, drowned peanuts and exploded watermelons.



Yet, many landscape sprinkler systems were still running.



Where were the rain shut-off devices?



Conservation and savings



Florida is one of a few states with a rain sensor statute. Since May 1991, new installations of irrigation systems have been required to include a rain shut-off device.



Florida Statute 373.62 states, "Any person who operates an automatic landscape system shall properly install, maintain and operate technology that inhibits or interrupts operation of the system during periods of sufficient moisture."



Thus, all automatic landscape irrigation systems require rain sensors or other shut-off devices such as soil-moisture sensor irrigation controllers.



Moisture sensing technology conserves water, saves money, reduces wear on irrigation system components, reduces disease and helps protect water resources from runoff.



If water costs and amount of water applied per watering cycle are known, it is easy to calculate how much money is saved when the sensor interrupts the cycle.



For example, if a system irrigates a half-acre of turf and is set to deliver a half-inch of water to each zone, approximately 13,576 gallons of water will be used during each watering event.



If the water costs $2 per thousand gallons, every time the sprinkler system comes on, the water bill will be $27.15.



Use a disc



The least expensive and most common rain sensor device is the expansion disc rain shut-off.



Expanding cork disks trigger a pressure switch. The expansion space can be easily adjusted by rotating the disc cover to a predetermined amount of rain required to trigger the switch. The amount of rain that will interrupt the irrigation system is marked on the adjustment cap.



A rain sensor must be mounted where it will be exposed to unobstructed rainfall — typically near the roofline on the side of a building.



The device can be tested during rainfall by setting out several straight-sided shallow containers, using the same technique as calibrating the irrigation system.



After rain has stopped, measure the water’s depth in each container with a ruler and calculate the average measurements. When the containers average a half-inch of rainfall, set the sensor to one-half inch and manually turn on the irrigation. The system should not run. If it does, a repair is needed.



Remember: Every drop that hits the ground will pick up pollutants as it flows to our groundwater. By only irrigating when the soil needs it, you are preventing contamination of drinking water.



Sheila Dunning is a Commercial Horticulture Extension agent at the Okaloosa County Extension office in Crestview.