Guide - show a BACnet water meter in the Energy dashboard

Goal: a BACnet object that counts water volume shows up in the Home Assistant Energy dashboard.

Before you start

The device is already added (see Getting started).
The meter is an analog object (Analog Input or Analog Value) in a volume unit: mL, L, m³, ft³ or gal. If the BACnet unit is another one, this guide does not apply.
You know the object by its name or number, for example AI 12.

Each BACnet device is its own entry, titled with the device name, under Settings → Devices & Services → BACnet IP. Click Configure on the entry of your device.
Choose Customize objects: type, COV, state class, properties.
In Objects to customize, search for your meter (by AI 12, instance or name) and pick it. Click Submit.
The next page shows the settings of that object. In this list every field starts with the object, for example Analog Value (4) - SP - type; the other fields of that object (COV, extra properties, other properties) look the same. Set:
- state class to Automatic. For a volume unit this gives Total increasing, which is what a meter needs.
- meter type to Water meter. (A gas meter in gal loses its device class, so gallons only work as a water meter.)
- type to sensor. An Analog Input is a sensor already. A writable Analog Value is a number by default, and the Energy dashboard only lists sensors, so change it in this same save.
Click Submit. The integration reloads by itself.

You should now see the entity as a sensor with a volume unit on the device page. The meter type makes it a water sensor.

The Energy dashboard now lists the sensor.

The Energy dashboard water consumption picker listing the sensor

Flow rates (L/h, m³/h, ...) need no setting at all. They work as water flow in the Energy dashboard as they are.

The sensor is not offered in the Energy dashboard: check that meter type is Water meter and that type is sensor, not number. BACnet units cannot tell water from gas or from a tank level, so without a meter type the sensor stays a plain volume that the dashboard does not list.
The value is a tank level or a "last month" total and not a counter: set state class to Measurement instead.
You changed the unit or state class and Home Assistant complains about statistics: open Developer tools → Statistics and click Fix issue once per sensor.