There is no single UK price per cubic metre
The exact cost depends on your appointed water and wastewater companies, charging zone and tariff. A combined metered bill normally applies separate clean-water and wastewater rates to each cubic metre, then adds fixed standing charges. Use the rates on your bill or company tariff sheet for a defensible figure.
To calculate your own marginal price, add the water unit rate and the wastewater unit rate after applying any stated return-to-sewer allowance. Do not divide a whole bill by usage without separating the fixed charges first.
Convert litres to cubic metres
Divide litres by 1,000. A household using 300 litres a day uses 109.5 m³ a year: 300 × 365 ÷ 1,000.
- 1,000 litres = 1 m³
- 10,000 litres = 10 m³
- 100 m³ = 100,000 litres
Why the wastewater volume can differ
Companies often assume a percentage of supplied water returns to the sewer, allowing for uses such as garden watering. The exact allowance varies, so use the tariff sheet for your company when checking a bill precisely.
Sources and further guidance
This guide provides general information. Your supplier’s tariff, bill and support-team advice take precedence for your account.