This is a very rapidly ...

This is a very rapidly changing field, especially with the advent of IoT type technologies such as Sigfox, LoRaWAN and soon NB IoT. I'd be very cautious with large scale roll outs unless you have flexibility to easily upgrade at least firmware, better even, hardware, in like the electronics and comms part.

Why not start with a small pilot to test all aspects (comms, data flow. connectivity, interoperability, reliability, etc) of these new technologies using piggyback solutions. We are about to install the first Sigfox and LoRaWAN based smart water meters in Australia, and would happy to share our experience.

Can I also challenge you with a different thought? Since the Majority of at least the smart water meter benefits come from better understanding the network, not the avoided manual meter reading costs, why not smart meter just 10% of your customers for 80% of the benefits at 20% of the cost? See our attached white paper.