Waterius (Ватериус) is an open-source Wi-Fi transmitter that reads the pulse output of water, gas, heat and electricity meters and forwards the readings over HTTP or MQTT to smart-home platforms, MQTT brokers or the waterius.ru service — it is aimed at homeowners and DIY makers who want automatic meter reading without replacing the meters they already have.

What it is

Waterius is a small embedded device built from two microcontrollers: an Attiny85 that counts pulses while sleeping and stores them in EEPROM, together with an ESP chip that provides Wi-Fi connectivity. The firmware is flashed to both chips, and the project lives squarely in the embedded IoT and smart-home ecosystem, using Arduino, Atmel ATtiny and ESP8266 tooling, I2C and industry-monitor concepts among its topic tags. A single unit accepts up to two meters and runs for roughly two to four years on three AA batteries.

The concrete problem it solves is manual meter reading and manual reporting. Rather than noting down figures and entering them by hand, an owner attaches Waterius to an existing meter that has a pulse output or reed switch, and the device transmits counts on a configurable schedule. When paired with the waterius.ru personal cabinet, it automatically submits readings to 157 water utilities (vodokanal) in Russia and the CIS, a figure given as of September 2025, and the service is an official partner of mos.ru. Readings can also be delivered by email, SMS and a Telegram bot, or received wherever the owner has programmed them to go.

Key capabilities

• Transmits readings over HTTP and MQTT, and can be pointed at a user-specified web server, MQTT broker, Blynk server or NTP server.
• Integrates with Yandex Smart Home, HomeAssistant (including discovery and an HAOS integration), Domoticz and SprutHub; WirenBoard is also supported.
• Supports all water meters with a pulse output, gas meters with a reed switch, the Betar SGBM-4 electronic gas meter, the Sanext Monu CU and Beril ITELMA STE 31 heat meters, and the Energomera CE101 and CE6803V 10-100A M7 R31 electricity meters.
• Determines the pulse weight automatically, picking 1 or 10 litres per impulse, so the owner does not need to know it in advance, and offers a manual pulse-weight setting as well.
• Accepts both "dry contact" and "NAMUR" meter outputs without configuration of the output type.
• Publishes to a waterius.ru account, a HomeAssistant instance, Domoticz, SprutHub, a custom HTTP/HTTPS endpoint, an MQTT client, or the httpwaterius web server with a simple UI.
• Ships with a reed-switch enclosure model for the BK-G4T gas meter (bk-g4t-sensor.zip).

Who uses it and how

• Households with pulse-output water meters that want readings filed automatically with one of the 157 supported water utilities through waterius.ru, including submission to the management company directly from the site.
• Smart-home operators who feed the device into HomeAssistant using Home_Assistant_setup.md and homeassistant.configuration.yaml, into the third-party waterius-ha integration, or into Domoticz and SprutHub via their own MQTT instructions.
• Makers who build the hardware themselves, following Making.md for the parts list and board creation, Firmware.md for flashing the Attiny85 and ESP, and Setup.md for installation and configuration.
• Owners of gas and heat installations who use the documented Betar, Sanext and ITELMA meter combinations, with community help in the waterius_forum Telegram chat, whose folk instructions are referenced in the README.

Getting started

A ready-made unit is purchased from waterius.ru, with setup described in the text and video manuals linked from the README. For a self-built device, firmware images are downloaded from the project's releases page and the build is completed by following Making.md, Firmware.md and Setup.md.

How it compares

No list of paid products that this project replaces is provided, and the README names no specific competing tools; it only links to a separate issue thread discussing factory-made and DIY analogues that users have compared. On the facts available here, Waterius stands alone in this registry.

When to use it — and when not to

A self-hoster who avoids the hosted waterius.ru cabinet must run their own MQTT broker, HTTP/HTTPS endpoint, Blynk server or NTP server, and must build and flash hardware rather than install software. It is unsuitable for meters without a pulse output or reed switch, since the device depends on counting impulses. The documentation is written primarily in Russian with a separate English translation, and the repository carries 51 open issues, so an English-speaking adopter should expect to rely on the community chat and translated files.