We have a largish house. There are 5 of us in it. The first thing I did when we moved here in 2001 was to ask the Water Authority to install a meter.
"Oh you don't want one of those, it will cost you a fortune"
"No it won't so will you please fit one"
"How many people live in the house?"
"Five"
"Oh you'll have huge bills with a water meter"
"Why are you trying to talk me out of it?"
"I am only trying to give you our best advice"
"Thank you for trying now when will you be fitting the water meter?"
Meter fitted five weeks later. First half yearly bill = 45% of the standard charges for a house of this size.
Consistently our bills are less than half the rate they want to charge if I didn't have the meter. They have changed the meter, determined that the original was reading incorrectly ~ same result. No wonder they didn't want me to have a meter.
We have a washing machine that is used daily and a dishwasher that is used twice a day, we have a bidet which is used a lot, all of which would suggest that we use a lot of water (just think of the number of times the toilets are flushed)
I still ponder the logic of charging for water depending on how many bedrooms you have.
A neighbour has 4 bedrooms (same as us) and no water meter. There are only two living in that house, they wash up by hand and only use the washing machine twice a week yet his water bill is twice the size of mine. It makes no sense unless you see it as a blatant rip off.