How to divide water consumption monitoring in HA, if there are two independent water sources - central distribution and a well (for watering only).
How do you tell what's being used currently (in general not just ha)
This will probably be switching back and forth between two utility meter integrations but you need to tell it how much goes on each so you either need a ratio or some kind of switching to know what's going on in real.
It's not cheap, and you need access to clamp it to the water line (and power near that) but you can get two of these:
You have to use their app to onboard the device, but it does support an HA integration. The only trick with two of them is that in their app you have to setup two separate houses. In HA they just both appear.
I'm using two of these just to detect hot water flowing to two showers (for presence detection basically). It's not their intended use, but they've worked really well for me.