Which device is commonly installed with a new irrigation controller to monitor rainfall?

• A. Rain Moisture Sensor
• B. Flow Meter
• C. Temperature Sensor
• D. Check Valve

Answer: (A)

Monitoring rainfall to control irrigation is a key factor in conserving water and preventing overwatering. A rain moisture sensor is the device commonly installed with a new irrigation controller because it detects when rain has fallen and signals the controller to skip or delay scheduled irrigation. This keeps watering from happening during or immediately after rain, aligning with weather-based scheduling and reducing waste.

Other devices have different roles and don’t monitor rainfall. A flow meter tracks how much water actually flows through the system, helping spot leaks or abnormal usage but not rainfall. A temperature sensor measures air or soil temperature, which can influence plant needs in some systems but doesn’t provide rain data. A check valve prevents backflow into the supply; it protects water quality but isn’t used to monitor rainfall.