WeKnowSmartHome

Rainwater tank monitor

A waterproof ultrasonic sensor measures how full your rainwater tank is. IntermediateWi-FiESP32ESPHome

Updated November 2026

Illustration of what you build. See the maker’s guide for photos of the real device.

Can I build this?

Estimated costLess than €30 (per the tutorial); €15–40 depending on parts (indicative)

Build timeNot stated

DifficultyIntermediate

Tools3D printer, computer to flash ESPHome

SolderingNo: the author did no soldering

3D printingYes: STL and 3MF files for the sensor holder are linked (PETG recommended)

What you need

ESP32 board
Waterproof ultrasonic distance sensor
USB cable and power supply
3D-printed sensor holder

How it works

Board: ESP32 (NodeMCU-32S)
Connects via: Wi-Fi with ESPHome
Made by: Simon Gillet

Good to know

Wi-Fi has to reach the tank; for a buried or distant tank, check the signal first.
Keep the electronics out of the tank: only the waterproof sensor head goes inside.

Build itTutorial by Simon GilletFull instructions, wiring and firmware from the maker →

This page summarises the maker’s project; the maker’s own guide is leading. Missing a tool? See In the toolbox. Need a better casing? See 3D printing & enclosures. Keep DIY builds to low voltage (USB or battery).

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