| Most states and/or cities in the U.S. now require | | | | the ease of installation and increased placement |
| rain sensors by law. They are simple to install and | | | | options offset the cost. Most wireless units come |
| pay for themselves quickly. | | | | with by-pass switches built into the device. |
| For this reason every lawn sprinkler system | | | | Some digital controllers also offer by-pass options |
| should have a rain sensor. The rain sensor | | | | for both wired devices and wireless rain sensors. |
| determines whether or not enough rainfall has | | | | No matter the type of rain sensor type that you |
| occurred in order to skip an irrigation cycle. | | | | choose, all rain sensors offer many advantages |
| There are 3 basic types of rain interrupters. They | | | | over not adding this detector to your automatic |
| all serve the same purpose: keeping your system | | | | sprinkler system. |
| from over-watering the turf or your garden. How | | | | Some of the immediate and long term benefits |
| does it do that? | | | | include: |
| The electrical connection between the sensor and | | | | - Saves Money. Whether you pay for city water |
| your sprinkler system controller is interrupted | | | | or spend electricity running a pump, the money |
| when a certain amount of rain triggers the device. | | | | you save over time will more than pay for the |
| The sensor breaks the electrical connection so | | | | rain sensor. |
| that electricity cannot flow to either the sprinkler | | | | - Extends Sprinkler System Life Span. Sprinklers |
| valves or to a pump start (if your system is on a | | | | are made up of gears and other parts that move. |
| well without a pressure tank). | | | | The less the sprinkler parts are used, the longer |
| One type breaks the connection by weighing the | | | | they last. |
| water in a rainfall collection cup. The problem with | | | | - Protects Water Resources. By limiting the over |
| this type is that leaves, sticks, or the occasional | | | | use of your sprinkler system, rain sensors reduce |
| lizard will find its way into the collection cup and | | | | excess water run-off that carries fertilizers and |
| therefore turning off the system. | | | | pest control chemicals into our shared water |
| The next type uses electrodes to determine how | | | | supply. |
| much water is in the collection cup. This kind of | | | | - Conserves Water. Less water is wasted when |
| rain sensor device also has a system problem of | | | | less supplemental water is needed for your turf |
| collecting things other than rainfall in the collection | | | | and in your garden. |
| cup. | | | | How much money can you save with a rain |
| The expansion disk type seems to be the most | | | | sensor device? It will vary based on your water |
| popular. This kind of sensor does not use a | | | | source (city, re-claim, or well) and where you live |
| collection cup; instead rainfall causes cork disks to | | | | (water costs, electrical rate, climate). |
| expand. This device uses a pressure switch to | | | | Here is one example that demonstrates the |
| break the electrical connection. These can be | | | | benefits listed above: Seminole County, Florida. |
| adjusted in increments of ¼" to the desired | | | | System Description: |
| rain fall setting. These adjustments can be | | | | Intended to sprinkle a 1/4 acre of turf calibrated |
| configured to kick in from 1 to a 1/2" of rain has | | | | to precipitate a half inch" of water every time the |
| fallen. | | | | system runs. |
| The most important aspect of installing a rain | | | | - This schedule would equal 6,788 gallons per |
| sensor is where to place it. It should be installed in | | | | irrigation cycle. |
| an area that is unobstructed by trees, roof over | | | | - This system (on City Water) pays $2.30 per |
| hangs, or anything else that might block rain from | | | | thousand gallons. |
| getting to the sensor. | | | | - Every time the rains sensor interrupts a |
| If it is a wired sensor, placement is generally near | | | | sprinkler cycle, you would save $15.61 |
| the sprinkler controller. The wires should be | | | | According to a recent study in Florida, the use of |
| connected inside the controller's valve wiring panel. | | | | a rain sensor device averaged a 45% savings in |
| This allows for easier electrical trouble-shooting of | | | | water for single-family residential water usage. |
| the system as the sensor can be easily | | | | The next time you see a sprinkler system running |
| disconnected. | | | | in the rain, you now know it doesn't have to be |
| Year by year, as technology improves, FM | | | | that way. Rain sensors save money, save our |
| sensors have become more popular. Although | | | | environment and save water. |
| they are more expensive than the wired devices, | | | | |