How much water does a pressure washer use?

Water usage depends on the machine type: domestic electric models use 5-7 litres per minute, petrol models 8-10 L/min, professional machines 10-15 L/min, and industrial units 15-25 L/min. This is still far less than a garden hose, which typically delivers 15-20 L/min without any pressure.

How much does pressure washing water cost?

UK mains water costs around £3.00-4.00 per cubic metre (1,000 litres). A 3-hour job using a professional machine at 12 L/min would use about 2,160 litres (2.16 m³), costing around £7-8 in water. Water costs are a relatively small part of the total job cost.

Can I use rainwater for pressure washing?

You can use collected rainwater, but it must be filtered before entering the pressure washer pump to remove debris, leaves and sediment that could damage internal components. Rainwater is naturally soft which is actually ideal for cleaning — it is free from limescale and can improve cleaning results.

How can I reduce water usage when pressure washing?

Use a rotary surface cleaner attachment for flat surfaces — it cleans faster and contains water splash. Pre-treat surfaces with detergent to reduce the pressure and time needed. Use the correct nozzle for the job — a 25° nozzle is more efficient than a 40° for most cleaning tasks.

CleanCalcs

Water Usage Calculator

Calculate total water consumption for pressure washing jobs by duration and flow rate.

Machine Type

Flow Rate

Check machine spec plate

Running Time (Hours)

Running Time (Minutes)

Water Cost

UK average ~£3.50/m³

How We Calculate This

How the calculation works

Water usage is simply flow rate multiplied by running time.

Typical flow rates

Domestic electric: 5-7 L/min
Domestic petrol: 8-10 L/min
Professional: 10-15 L/min
Industrial: 15-25 L/min

Formulae

Total litres = flow rate (L/min) × time (minutes)

Cubic metres = total litres ÷ 1,000

Water cost = cubic metres × cost per m³

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify quantities and timings for your specific situation.