What’s the difference between metered and rateable value water?

If you have a water meter in your property, your water bills will be based on actual consumption, similar to the way that energy is billed. Rateable values are used by water companies to work out how much to charge people without a water meter. They were used for everyone's bills until 1990. The values were assessed and changed by the Valuation Office of the Inland Revenue and were loosely based on the annual rental value of the property.