Reading out analog meters

I doubt that very much - where does the power for it come from?

Many people have this working. There’s a lot in the Archive (old forum). Here’s one thread:
Gas meter reed switch debounce (polled, via interrupt-driven timer): Gas monitoring | Archived Forum

But I’ve just noticed - the search facility on the old forum has disappeared. @glyn.hudson or @TrystanLea - why is this?

There are many suppliers. The main point is it needs to be for potable (drinking) water. The maximum flow rate (pipe size) will need to be similar to your existing meter, and the pulse rate high enough to give the resolution you want and slow enough to count reliably. You’ll need to work that out based on the maximum flow rate that you need.
Water meter suggestions: A sensor recommendation for a water meter dial | Archived Forum

I’ve elevated your permissions so you should be able to post pictures here. Please don’t put them on a third-party site with a link.