Glossary

Systems of metering for calculating water consumption, and thereby charges owed by the customer per unit of water consumed, are needed in cases where charges or tariffs for water are not set at a flat rate per user. However, it is important to recognise that metering is expensive to install and operate efficiently, and that users are likely to reduce their usage, so that it may not be economic – however apparently desirable – to install a metering system. Any decision to install metering will have to take many factors into account: the value and scarcity/abundance of water; the cost of installing meters, maintaining their security, staffing their inspection, billing customers, etc.; possible customer reactions; the desirability and practicalities of introducing a two-tier payment system, whereby above a certain level, price per unit increases, thus helping reduce waste and increase revenues. Most OECD countries, and a growing number of other countries, use metering for urban domestic water consumption. (See also Tariff structures.)