Pressure Washer Time & Water Calculator
Knowing roughly how long a cleaning job will take — and how much water it will use — helps you plan your day and stay mindful of any local water restrictions. Enter the area you need to clean, the surface type, and your washer's flow rate below.
Estimate cleaning time and water use
Enter the area you need to clean, the surface type, and your washer's flow rate.
Most domestic pressure washers run 5-9 L/min.
Moderate pace for textured slabs
Cleaning 20m² of patio / paving slabs will take approximately:
14 minutes
Using around 94 litres of water at that flow rate — worth checking against any hosepipe ban restrictions in your area.
Recommended products
A few well-reviewed pressure washers for outdoor cleaning jobs.
£249.00
Pros
- LED pressure ring on the spray gun shows selected pressure setting
- 130 bar output tackles driveways and patios with ease
- Includes patio cleaner and dirt blaster nozzle
Cons
- Hose reel not included on this model
£124.00
Pros
- Compact and light enough to store in a cupboard
- Simple to set up with no tools required
- Home and Car kit included with patio cleaner and wash brush
Cons
- 120 bar output struggles with ground-in driveway grime
£449.00
Pros
- 180 bar output cuts driveway cleaning time significantly
- Integrated hose reel keeps the hose tidy
- Five-year warranty on registration
Cons
- Overkill for occasional light cleaning
- Larger footprint needs shed or garage storage
Frequently asked questions
Why does surface type change the cleaning time so much?
Textured or uneven surfaces like decking and patio slabs need slower, more careful passes to clean grooves and joints properly, while flat, hard surfaces like driveways and block paving can be covered more quickly with wide sweeping passes.
Does a higher pressure washer flow rate always clean faster?
A higher flow rate delivers more water per minute, which generally helps rinse away dirt faster, but technique and nozzle choice matter too — a narrow, high-pressure jet used too close can also slow you down by damaging softer surfaces like decking, forcing more careful, slower passes.
Do I need to worry about hosepipe bans?
Yes — during a hosepipe ban, using a pressure washer connected to the mains supply is typically restricted in the same way as a garden hose. Check your water supplier's current restrictions before starting a large job.
How can I reduce water use when pressure washing?
Sweep or brush away loose debris first so the washer isn't rinsing away dry dirt, work in manageable sections rather than randomly, and choose a nozzle appropriate to the surface so you don't need repeat passes.