Engineer Kevin Darrah has published a video showcasing a water meter monitoring project based on an Espressif ESP32 development board and the Adafruit IO platform — after finding his water bill had doubled in a month.
"Last month our water bill showed that the usage doubled," Darrah explains in the video's introduction. "I'm going to show you how I got to the bottom of that using an ESP32 to monitor the water meter. And since we have the ESP32 on there I'm able to send the data up once a minute here to [Adafruit IO]. So we can monitor everything from showers, toilet flushes, doing the laundry, maybe you've got a leak somewhere."
Darrah's build doesn't touch the water directly, but instead monitors the output of his existing water meter using a Hall effect sensor to detect when a magnetic wheel in the meter completes a rotation. The project is based on an earlier build by Instructables user Gregory0, which was powered by an Arduino development board linked via a filtering circuit to a high-sensitivity Honeywell SS494B Hall effect sensor and simply printed its output via local serial connection.
The project isn't quite as simple as it sounds. As well as amplification and filtering, the build may need to be adjusted depending on the type of water meter in use. Some manufacturers sue a two-pole magnet, while others use a four-pole magnet; measuring based on the wrong type of magnet could double or halve the real-world reading.
Darrah's projects can be followed on his YouTube channel — though while he says the build allowed him to find the source of his high water usage, he's saving the big reveal for a future video.