Our R E C @ farm when updating their "switch makes sense system" went to similar for electric about 7-8 years ago. Now they don't have 2 F T & 1 P T guys in pickups driving around several counties reading meters 5 days a week. Got rid of 3 4x4 pickups & 2+ men. 

 Both systems send useage data at to a central computer.  

The term 'smart meter' is a bit of misnomer... there's nothing of any exceptional intelligence, it's just a meter that has a short-range data transmitter.  There's a receiver unit in a vehicle, when they drive down the neighborhood, it gathers up all the meter readings and transmits them to the utility's computer system for billing.

It is 'smart' in that it allows a part-time wage-earner to accomplish an entire city read in the time it would have taken 100 walking readers to do a couple neighborhoods.  To make things even more 'streamlined', many utility companies have their billing system set up to process based on 'estimation' on their regular billing date, and at the next billing date, they add or subtract from that estimation based on whatever usage volume change occurred at the read date.

The way they accomplish this is pretty simple... they have a year or two's worth of readings, and their system computes a 'daily average'.  Let's say that your daily average for a given weekday (like a Monday) is 200 gallons, and that's about same per day 'till Friday, when you might use 350, and 500 on Saturday, 400 on Sunday... like you're watering flowers, washing a car, or just taking a few more showers after doing yard work...  so the billing system says your meter was at 21843 on Saturday the 1st... and they're billing you through the following 30'th, they say the daily average of all those days would likely put you at so many mondays, tuesdays etc., on the average... and they bill you for that.  Now, halfway through the month, they get a reading that says you're slightly LESS by THAT day, than your daily average... so they apply a little math (integration and derivation) to 'weight' the next month's daily averages.  By three-four months, with over 2 years' meter records, they'll have that bill down to really-darned-close.

UNLESS you have a leak somewhere... a running toilet, or a broken irrigation line in your yard...

in which case, the 'smart meter' really isn't about the METERING, it's about the DATA HANDLING... that averaging and weighting (it's calculus, man) is saying that your daily usage trajectory has significantly departed from your past use, and they might add a note to your bill and say that your usage is up uncharacteristically higher since say.. June... and that prompts to you consider checking for leaks, or to acknowledge that you planted 5 new trees in May, and have been diligently watering them in.