We could all be paying for our water differently in the future
The sturdy old meter has come a long way, but having done so much for gas and electricity, is it about to take over water - and the world?
If you're a person who uses hot water much more carefully than you use cold water, then you're one of the reasons why conservationists like water metering.
Making us pay for things seems to change our mindsets towards it.
It's not just about getting us to fill the sink with less water, it's also about getting manufacturers to make appliances that use less water.
When people pay for water indirectly, they don't know that - according to water regulator Ofwat - an average bath costs about 15 pence to fill, a toilet flush about 1.5p, a machine wash about 11p and an hour using a hosepipe about 95p.
They don't know they can save.
EVERYDAY WATER COSTS
Toilet flush: 1.5p
Washing machine: 11p
Hour of hosepipe: 95p
Some evidence of people responding to water meters comes from a trial in the Isle of Wight where, in the 1980s, 48,000 homes were compulsorily metered.
Most of the Isle of Wight was metered, but nearby Hampshire was not.
There was an effect on consumption on the island. It fell back at first, but later rose again.
However, compare the results to water demand in water meter-free Hampshire and you see that the Isle of Wight used about 10% less than you might have expected without metering.
Meters, in some shape or form, have been with us for some time
The onward march of the meter is just part of a bigger trend towards a pay-as-you-go society, from parking spaces to road space to sports on TV.
And the next step is for pricing and for meters to become more sophisticated.
For example, new-style congestion charging gantries in South London are
effectively an experiment in road metering.
This new technology could eventually allow time-of-day pricing.
UK energy regulator Ofgem is looking at smart meters - essentially, remotely readable ones that tell us the current price.
"Meters have become hot news because energy prices are up 70% in the year, and clearly consumers will be interested if they can save costs by having a meter on their kitchen wall," says Ofgem chief executive Alistair Buchanan.
"It can also benefit the government's energy efficiency drive and low carbon agenda," he adds.
From humble beginnings, it could just be that the meter is coming of age.