What is typical UK mains water pressure?

UK mains water pressure is typically 1-4 bar, with 3 bar being common. Check with your water supplier or use a pressure gauge.

Does hose length affect flow rate?

Yes. Longer hoses have more friction loss, reducing flow. A 50m hose delivers significantly less than a 15m hose at the same pressure.

12.5mm (1/2 inch) is standard and suits most gardens. 19mm (3/4 inch) is better for large gardens or when running multiple sprinklers.

Time how long it takes to fill a 10-litre bucket. Divide 10 by the seconds and multiply by 60 for litres per minute.

Yes. Longer hoses have more friction loss, reducing flow rate. A 30m hose delivers roughly 20-30% less water than a 10m hose at the same pressure.

Estimate water flow rate based on hose diameter and pressure.

Hose Diameter

Hose Length

Water Pressure

Flow rate is estimated using pipe diameter, pressure, and friction loss over the hose length.

Actual flow rates depend on many factors including fittings, bends, and mains supply capacity. Use a bucket test for accurate measurement.

Friction loss is estimated at 2% per metre of hose length.

Calculate the ideal water butt size based on your roof area and rainfall.

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Work out sprinkler placement and overlap for even lawn coverage.

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Last updated: February 2026

All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.