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Estimate uses a typical combined water + sewerage rate of about GBP 3.70 per cubic metre plus GBP 80/year standing charges; your water company's rates vary. In England and Wales you can usually switch back within 12-24 months if the meter costs more. Meters are fitted free on request.
What The Water Meter Calculator Works Out
- Estimated metered bill: people x litres per person per day x 365, in cubic metres, x a typical combined water and sewerage rate of GBP 3.70 per m3, plus about GBP 80 a year of standing charges. Two average users get through about 104 m3 a year, roughly GBP 380 to GBP 400 metered.
- Verdict: your unmetered bill less the metered estimate. A gap of under GBP 20 either way is "too close to call", which is an argument for trying the meter rather than waiting: in England and Wales you can usually switch back within 12 to 24 months if it loses, and meters are fitted free on request.
- Rule of thumb: unmetered bills are charged on a property's 1990 rateable value, a fossilised proxy for house size, so the classic winner from metering is few people in many bedrooms.
- Household water use: average consumption is about 142 litres per person per day, showers and toilets doing most of it; careful households run a quarter below that and garden-and-teenager households well above.
- Rates and standing charges (advanced): enter your own company's metered rate per cubic metre and its fixed charges, which vary considerably between regions.
- Own use, garden and leaks (advanced): use a measured litres-per-person figure, add cubic metres for garden watering, a pool or a hot tub, and price a leaking toilet: a silently running cistern can waste 200 to 400 litres a day, free to you unmetered and pounds a week on a meter. The meter also acts as a leak detector, since a ticking dial with everything off is the early warning unmetered homes never get.
- Metered bill per month and break-even use (advanced): the monthly comparison, and the annual cubic metres (and litres per person per day) at which the two bills are equal, so you can see how much headroom you have.
- Bedrooms versus people (advanced): applies the folk rule to your own house.
- Difference over five years (advanced): the annual saving or extra cost x 5 at today's prices. Where a meter cannot physically be fitted, companies offer assessed charges, often themselves cheaper than rateable value; Scotland runs unmetered by default via Council Tax, and some southern English companies are metering compulsorily under water-stress rules.
Further reading: CCW (the water watchdog): metering and saving.