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A garden sprinkler flows ~1,000 litres/hour: on a meter (water + sewerage ~GBP 4 per 1,000L) that's GBP 4/hour: the garden's most expensive appliance after the hot tub. Hosepipe bans typically cover sprinklers FIRST. The alternatives ladder: water butt (free rain, see our water butt page), drip/seep hoses (a tenth of the flow to the roots where it matters), evening watering (halves evaporation), and the lawn truth on the right.
What The Sprinkler Cost Calculator Works Out
- Water used per summer: hours a week x weeks x the sprinkler's flow rate. A standard oscillating or rotary head passes about 1,000 litres an hour, a bath every six minutes, so the casual four-hours-a-week habit over ten weeks uses 40,000 litres.
- Cost per summer: litres divided by 1,000 and multiplied by the combined water and sewerage charge, around GBP 4 per cubic metre on a meter. That makes the sprinkler a GBP 4-an-hour appliance and the example GBP 160 a season. Unmetered homes pay nothing extra, though heavy garden watering is among the grounds on which a company can insist on a meter.
- The lawn truth: established lawns do not die in drought; they go dormant, brown, and green again with the first sustained rain. Lawn watering is cosmetic. This year's plantings, containers, fruiting vegetables and anything in a rain shadow genuinely need the water.
- Flow rate and water price (advanced): edit for your sprinkler (impact and rotary heads range 600 to 1,500 litres an hour) and your water company's volumetric charge, which varies from about GBP 3 to GBP 5.50 per cubic metre including sewerage.
- Evening watering (advanced): watering after dusk cuts evaporation loss, so the same soil moisture needs less water; enter the share you would save, typically 30% to 50%.
- Per hour and per week (advanced): the running cost of an hour's sprinkling and the weekly bill and litres, with the daily average.
- Drip hose for the same hours (advanced): a drip or seep line runs at roughly a tenth of the sprinkler's flow, straight to root zones. The card prices the same hours at your drip flow rate and shows the percentage of water saved.
- Drip kit payback (advanced): how many weeks a GBP 20 to GBP 40 drip line and timer take to repay from the metered saving, usually within the first summer. A timer-and-drip combination also automates holiday cover.
- Water butt fills (advanced): how many times a butt of your chosen size would need to fill to replace the mains water used. A 200-litre butt refills from one roof downpipe in a good downpour, and butt water keeps the beds alive through a hosepipe ban.