Not sure if water is energy but it shows on the energy DB, so I figure I’ll start here.
I’m trying to submeter my house with two meters I can monitor in HA. One for indoor, one for outdoor (mostly irrigation). I have automated valves to control these, so I can use the data.
I bought a well known Positive Displacement meter. It’s built like a brick house and my goal is to have two but I wanted to do some testing. It has a pulse counter output. My Greeneye is happy with it. I have put it up on a (very wet 
) bench and tested it. It seems accurate down to just below a gallon per minute. Then, at some point, it stops counting at all. This makes one of the primary use cases - detecting small leaks - pretty much impossible. It will detect 1/2 gallon of water, but only if it flows in less than a minute.
I need to redo my tests to confirm, my pipe soldering skills left a little to be desired and I had a failure, so rebuilding.
What I did notice during my tests is that the meeter the utility uses (a Hershey) was startlingly accurate, down to a trickle. I can get a couple of these on eBay but I need to get the Translator Register Encoder to read it. This isn’t a pulse counter. It’s some form of three wire serial interface (maybe 1-wire or I2T) and Hershey says it outputs totals in ASCII. If I can interface to it.
This seems to be covered in AWWA C707 standard but I can’t get hold of this. Has anyone been down this path? This meter seems amazingly accurate at low flow. I’m obsessing here because the one time we had a leak when we were away for 2 weeks it was slow, but over that time it did a ton of damage.
Thanks for any pointers or ideas.