I also like Comatose’s pressure monitoring. The pressure fluctuation can probably countered by only looking at pressure differences between starting pressure, operating pressure and final ending pressure (per station). That means you’ll have to add a delay between activating stations to get a proper reading which might have another knock-on effect when using a master zone to activate a pump as then you’ll have to use a different pressure algorithm altogether as the pump should compensate for pressure fluctuations during an irrigation cycle and you would not want all closed valves while the pump is running.
It’s a slippery slope, but I can sense a solution at the bottom 😉
This of course creates even more headaches for Ray who yet to provide separate rain and flow sensors and I of course would want two flow sensors so I can also monitor any high usage or slow leaks on my main line to the house and not just on the irrigation line 🙂
The problem with leaks is that your probably only know for sure after month three when the second high water bill arrives. This can be a hefty bill which is even worse when it co-incides with water restrictions, so well worth installing some sort of warning system.
Either way I would be keen on either solution.