[RandallFlagg]

THis is a hoax. THey can’t measure your water that you flush down the drain.

Actually, it's quite easy. It'll either be done with an average estimate from water used, or a flow meter to the waste piping -which they own.
The water folks here can tell what my bill is by simply driving by and activating a radio receiver for my meter's transmitter. They don't even have to stop to read it.

[mamelukesabre]

I doubt you understand the principle. Supply pipes are pressurized and full, as in no air space. Sewage pipes are what is referred to as open channel flow. THey can’t meter that very easily.