What is a rain sensor, anyway?

A rain sensor or rain switch is a switching device activated by rainfall. There are two main applications for rain sensors. The first is a water conservation device connected to an automatic irrigation system that causes the system to shut down in the event of rainfall.

How does a rain sensor work?

In most cases, a rain sensor acts as a simple on/off switch. As moisture-absorbing disks expand, they activate a switch that interrupts the circuit from the controller to the solenoid valves. Once the rain sensor has dried out, the switch deactivates - this allows for normal operation.


Rain sensors, by their nature, are reactive to rain events.
This differs from Rachio's proactive approach to checking the local weather forecasts. Rachio takes these predictions and compares them to the Rain Skip threshold you select within the Rachio App.

How does Rachio use rain sensors?

Rain sensors are useful as a sort of "insurance policy" against inaccurate data from your local weather station(s). Unlike Rachio's Rain Skip feature, however, a schedule skip due to an activated rain sensor does not get recorded as rain savings.

The Rachio does not need a rain sensor to operate, but the unit can take the input from existing rain sensors - interrupting the [common wire] signal.

Rachio's Weather Intelligence features take a broader view of the weather, factoring in the last time the sprinkler system ran, the amount of precipitation since the last time the system ran, the temperature that affects evaporation, forecast for precipitation rates until the next time your system can run, seasonality, and more.

A rain sensor can help but is strictly supplemental.

Supported Rain Sensors

The Rachio needs a normally closed (NC) rain sensor, which interrupts the common wire when activated. The Rachio supports BOTH wired and wireless rain sensors.

Supported Rain Sensors (Click name for Specs & Instructions)

Rain Sensor Setup

How do I connect a rain sensor?

Every rain sensor is a bit different and not all wiring colors are the same.
For specific instructions, please choose your Rachio model, below:


If you need additional help with your rain sensor wiring, feel free to reach out to our community forums with a photo of your wiring, along with the make & model of the rain sensor, or contact Rachio Support.

How do I enable my rain sensor in the Rachio App?

To activate, simply log into the Rachio app (mobile recommended) and go to the "More" tab, select "Controller Settings" and then "Accessories". Sensor toggles are found under Sensor (Terminal 1 or Terminal 2). For further instructions, choose your device below:


If the rain sensor is triggered, no schedules will run at their prescribed times. However, manual schedules (via the remote control) will run even if the rain sensor is triggered.

Test & Troubleshoot


To prevent severe equipment damage, never connect the Rain Sensor to any power source greater than 24 VAC. If you are in doubt, contact a qualified installer or electrician. The Sensor should be inspected for damage and manually tested regularly to ensure proper operation.

How can I test my rain sensor?

A very simple test will ensure that your Rain Sensor is operational. Please see the following article for instructions: How to test a rain sensor.

What do the app notifications tell me about my rain sensor?

The status of your rain sensor will be shown within the Rachio App, under "More" and then the "History" tab.
For further details, please visit our article on Rain Sensor Notifications.

Will I need to clean/maintain my rain sensor?

Periodic cleaning is definitely recommended and is an important first step in troubleshooting. If you're noticing frequent on/off notifications, try the tips recommended in this article: Rain Sensor Cleaning.

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