ESP32 - Water Sensor - Pump
In this tutorial, we will learn how to use an ESP32 to activate a pump for draining water when it is detected by a water sensor. In other words, we will be discovering how to create an automatic drainage system using an ESP32, a water sensor, and a pump
Hardware Used In This Tutorial
Or you can buy the following sensor kit:
1 | × | DIYables Sensor Kit 30 types, 69 units |
Introduction to Water Sensor and Pump
If you do not know about water sensor and pump (pinout, how it works, how to program ...), learn about them in the following tutorials:
- ESP32 - Water Sensor tutorial
- ESP32 - controls pump tutorial
How the Automatic Drainage System Works
ESP32 periodically reads the value from the water sensor, then:
- If the value is greater than a pre-defined threshold, ESP32 turns on the relay to activate the pump.
- Otherwise, ESP32 turns off the pump.
Wiring Diagram

This image is created using Fritzing. Click to enlarge image
If you're unfamiliar with how to supply power to the ESP32 and other components, you can find guidance in the following tutorial: How to Power ESP32.
ESP32 Code
Quick Instructions
- If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
- Do the wiring as above image.
- Connect the ESP32 board to your PC via a micro USB cable
- Open Arduino IDE on your PC.
- Select the right ESP32 board (e.g. ESP32 Dev Module) and COM port.
- Copy the above code and open with Arduino IDE
- Click Upload button on Arduino IDE to upload code to ESP32

- Put the water sensor into the water
- See the pump's state
Code Explanation
Read the line-by-line explanation in comment lines of source code!
Video Tutorial
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