These small devices play a critical role in conserving water by keeping your irrigation system from running while it’s raining.
Rain sensors are a common component in modern irrigation systems, but many homeowners may not fully understand how they work. These small devices play a critical role in conserving water by preventing your irrigation system from running while it’s raining.
How rain sensors work
Inside rain sensors are small cork discs, also known as hygroscopic discs. When it rains, these discs absorb moisture and expand. This activates a switch that interrupts the signal between the irrigation controller and valves, preventing the system from running.
Once the discs dry out, they shrink back to their original size, allowing the irrigation system to resume its normal schedule.
If you’ve ever noticed your sprinkler system running while it’s raining, there may be a problem with the rain sensor. Some common causes include:
- The rain sensor has reached the end of its lifespan.
- A wiring issue in wired sensors.
- A dead or low battery in wireless sensors.
Identifying the cause early can help prevent water waste. To make sure rain sensor is functioning properly, follow these simple steps.
Bypass settings and common mistakes
When a wired rain sensor malfunctions, it can sometimes prevent the irrigation system from running at all. In response, homeowners may switch the controller from “Active” to “Bypass.
While this temporarily restores irrigation, it also disables the rain sensor entirely. This means your system will continue to run even during rainfall, defeating the purpose of having the sensor at all.
It’s better to address the underlying issue than leaving the sensor inactive.
Maintenance and replacement
Rain sensors are not a one-time installation. Over time, the internal discs can deteriorate and lose their effectiveness. As a general guideline, plan to replace the rain sensor every three to five years.
Replacement costs typically range from $40 to $115, depending on whether you choose a wired or wireless model. Regular maintenance and timely replacement will ensure your system continues to operate efficiently.
If you suspect your rain sensor is not functioning properly, consider contacting a licensed irrigation professional. They can diagnose wiring issues, replace faulty components and ensure your system is operating as intended.
Of course, if you’re comfortable and confident with DIY repairs, you can find many step-by-step resources available online.
