Garden Sprinkler Problems: Why Has Your Rain Sensor Stopped Working?

When you had your irrigation sprinkler system installed, you may have added a rain sensor to the sprinkler. These sensors are a handy way to save water and avoid over-watering your lawn. 

Rain sensors are really useful if you have automatic settings on your system and you aren't around to turn things off in rainy weather. Without a rain sensor, the sprinkler will carry on watering even in a downpour; a sensor simply does the sensible thing and shuts the system down until the rain stops.

If you've opted to have a rain sensor, then you'll be a bit perturbed if you look out of the window and see that your sprinkler is merrily watering your garden even though it is raining.

Why isn't your rain sensor doing its job?

Check Sensor Settings

First, check if the sensor is working. It will have a manual override that should turn the sprinkler off when you push or flick the switch. If the sprinkler stops when you use this switch, then the unit is working.

Now, you need to work out why it hasn't stopped the sprinkler in the rain.

This can be due to a couple of reasons:

  • Sensor settings: Rain sensors don't work every time it rains. They have settings that tell the sensor to shut off the sprinkler when rainfall gets to a certain level. If your sensor hasn't activated the shut-off, then its settings may have moved or need to be changed. Look at the sensor. You'll usually see an area with switch slots in it. The activation switch will be in one of these slots. If it is in the wrong slot, change it back. If it's in the right slot, move it to a lower setting.
  • On/off switch: Most rain sensors have a manual on/off switch. Check that this is switched on. If it isn't, then turn it on.

If either of these fixes work, then the sensor should start controlling the sprinkler again. If not, you have a different problem.

Look for Other Problems

If you're handy, then you may find a fix you can do yourself in the rain sensor or sprinkler manual. For example, sensors sometimes don't work because the sprinkler's jumper wire hasn't been disconnected. This jumper controls the sprinkler and needs to be bypassed for a rain sensor to work. You may also have a problem with your water connection.

If you aren't confident trying further fixes yourself or if nothing seems to get the sensor working, then call out your plumber. They will work out where the problem lies and fix it.