How Much Water Does a Pressure Washer Use? | NZ Guide
How Much Water Does a Pressure Washer Use?
If you're considering a commercial water blaster or pressure washer, you may be wondering how much water it actually uses.
The answer depends on the machine.
Pressure washers can have significantly different flow rates, generally expressed in litres per hour (L/h) or litres per minute (L/min).
But there's an important point that's easily overlooked:
A pressure washer with a higher litres-per-hour rating doesn't necessarily use more water to complete a cleaning job.
Why? Because cleaning time matters too.
A commercial pressure washer capable of cleaning an area faster could potentially operate for less time than a lower-flow machine.
So when comparing water consumption, don't look at litres per hour alone. Consider water flow + cleaning performance + operating time + the job being completed.
In this guide, Hygiene Direct explains how pressure washer water consumption works and what New Zealand businesses should consider when choosing a commercial machine.
Browse our complete range of Commercial Water Blasters & Pressure Washers.
How Is Pressure Washer Water Usage Measured?
Pressure washer water flow is commonly specified in:
Litres per hour (L/h)
or:
Litres per minute (L/min)
Converting between the two is straightforward.
For example:
600 L/h ÷ 60 = 10 L/min
So a pressure washer delivering 600 litres per hour has a nominal flow rate of 10 litres per minute at that stated operating condition.
However, that doesn't mean every time you use the machine it will consume exactly 600 litres.
It means that if it operated continuously at that stated flow for one hour, the theoretical volume would be 600 litres.
Actual consumption depends on how the machine is operated.
How Much Water Does a Commercial Pressure Washer Use?
There isn't one figure for every commercial machine.
For example, within the Nilfisk commercial machines we've been working with at Hygiene Direct:
Nilfisk MC 2C 120/520 XT
Maximum water flow: 520 L/h
Nilfisk MC 4M 160/620
Maximum water flow: 620 L/h
Nilfisk MC 5M 115/700
Maximum water flow: 700 L/h
Nilfisk MH 3C 145/600 PA
Maximum water flow: 600 L/h
That demonstrates why it's important to check the specifications of the individual pressure washer.
A larger number isn't automatically good or bad.
It tells you something about the machine's water-delivery capability.
Convert Litres Per Hour to Litres Per Minute
For many people, litres per minute is easier to visualise.
Simply divide litres per hour by 60.
Using the examples above:
| Water Flow | Approx. Litres Per Minute |
|---|---|
| 520 L/h | 8.7 L/min |
| 600 L/h | 10.0 L/min |
| 620 L/h | 10.3 L/min |
| 700 L/h | 11.7 L/min |
This makes it easier to estimate potential water use over a particular period.
For example, at a nominal flow of 10 L/min:
10 minutes = 100 litres
20 minutes = 200 litres
30 minutes = 300 litres
60 minutes = 600 litres
Again, that's a simple theoretical calculation based on continuous operation at that flow.
Does a Pressure Washer Use Less Water Than a Garden Hose?
You'll often hear claims that pressure washers use substantially less water than ordinary garden hoses.
That can be true in some comparisons, but we wouldn't give you a universal percentage.
Garden hose flow varies depending on:
- Water pressure
- Hose diameter
- Hose length
- Tap
- Nozzle
- Restrictions in the system
Pressure washer flow also varies between machines.
The correct comparison is therefore:
Actual hose flow × cleaning time
versus:
Pressure washer flow × cleaning time
There is another important factor.
A pressure washer increases the cleaning effectiveness of the water by delivering it at significantly higher pressure.
That can allow certain cleaning tasks to be completed differently or faster than simply rinsing with a hose.
So don't rely on a generic claim such as:
“A pressure washer saves X% water.”
Compare the actual application instead.
Why Higher Water Flow Isn't Necessarily Wasteful
This is particularly important when buying commercial cleaning equipment.
Imagine two hypothetical pressure washers.
Machine A
Flow rate: 500 L/h
Cleaning time: 60 minutes
Potential operating volume:
500 litres
Machine B
Flow rate: 700 L/h
Cleaning time: 35 minutes
Potential operating volume:
408 litres
Despite having the higher hourly flow rate, Machine B would use less water in this hypothetical example because it completed the job considerably faster.
This doesn't mean a 700 L/h machine will always use less water than a 500 L/h machine.
It illustrates why L/h alone isn't a measure of water efficiency.
You need to know how efficiently the machine completes the actual cleaning task.
Pressure and Water Flow Work Together
When comparing pressure washers, it's useful to understand the different roles of pressure and flow.
Pressure
Helps loosen contamination from the surface.
Water Flow
Helps carry the loosened contamination away.
Imagine blasting thick mud from a piece of construction equipment.
Pressure can break the mud away.
But once it's loose, you need sufficient water to move it off the machine.
For large commercial cleaning tasks, adequate water flow can therefore contribute significantly to productivity.
Does Higher PSI Mean More Water Use?
Not necessarily.
PSI and water flow measure different things.
PSI measures pressure.
L/h measures water flow.
You can therefore have two machines with different combinations of pressure and flow.
That's why we recommend comparing:
Pressure + flow + intended duty + application
rather than choosing a water blaster solely because it advertises the highest PSI.
For more information, read:
What PSI Water Blaster Do I Need?
How Much Water Does a Pressure Washer Use in 10 Minutes?
You can estimate this from the machine's flow rate.
For example:
520 L/h
520 ÷ 60 = approximately 8.7 L/min
Over 10 minutes:
approximately 87 litres
600 L/h
600 ÷ 60 = 10 L/min
Over 10 minutes:
approximately 100 litres
700 L/h
700 ÷ 60 = approximately 11.7 L/min
Over 10 minutes:
approximately 117 litres
These are straightforward theoretical calculations based on the stated flow continuing throughout that period.
Actual usage can vary according to operation and machine specifications.
How Much Water Does a Pressure Washer Use in 30 Minutes?
Using the same calculation:
| Flow Rate | Approx. Water in 30 Minutes |
|---|---|
| 520 L/h | 260 L |
| 600 L/h | 300 L |
| 620 L/h | 310 L |
| 700 L/h | 350 L |
But remember:
Thirty minutes of trigger time isn't necessarily the same as thirty minutes spent on the cleaning job.
An operator may stop spraying while:
- Repositioning equipment
- Applying detergent
- Moving objects
- Inspecting the surface
- Changing accessories
So these figures are useful estimates rather than guaranteed job consumption.
How Much Water Does a Pressure Washer Use Per Hour?
If the machine's flow specification is stated in L/h, this is straightforward.
A pressure washer rated at:
520 L/h
has a nominal hourly flow of 520 litres under the stated conditions.
Likewise:
700 L/h = 700 litres per hour
if water were flowing continuously at that rate.
But for a commercial business, water per completed cleaning job can be a more useful measure than water per hour.
Measure Water Use Per Job
If water efficiency matters to your business, this is a much better approach.
Instead of simply recording:
Our pressure washer uses 600 L/h
measure:
How much water do we use to complete this particular cleaning task?
For example:
Cleaning one truck
Cleaning one machine
Cleaning 100 m² of concrete
Cleaning one workshop area
Then compare that against:
- Cleaning time
- Labour
- Detergent consumption
- Cleaning result
That gives you a much more meaningful picture of operational efficiency.
Why Cleaning Time Matters
For commercial users, water isn't the only resource being consumed.
You're also paying for labour.
Imagine a cleaner takes:
60 minutes
to complete a task with one machine and:
40 minutes
with another.
That 20-minute difference repeated across hundreds of cleaning jobs can become significant.
This is why choosing a commercial pressure washer shouldn't focus entirely on:
purchase price
PSI
or:
water flow
in isolation.
The objective is to achieve the required cleaning standard using an efficient combination of:
equipment + water + chemistry + labour + time
Can You Reduce Pressure Washer Water Consumption?
Potentially, particularly by improving the overall cleaning process.
Here are some practical considerations.
Use the Right Machine
An underpowered or poorly matched machine may require considerably more cleaning time.
Use the Correct Nozzle
The appropriate nozzle can improve how effectively the water reaches the surface.
Use Appropriate Cleaning Chemistry
Where suitable, a detergent can help loosen contamination so the water blaster doesn't need to do all the work through mechanical force alone.
Allow Appropriate Contact Time
Giving a cleaning product the correct dwell time can improve cleaning effectiveness.
Never allow a chemical to dry on a surface unless the product instructions specifically permit it.
Clean Systematically
Randomly moving around an area can result in repeated cleaning of the same sections.
Maintain the Machine
Poorly maintained equipment may not perform as intended.
We'll cover this in:
Pressure Washer Maintenance Guide
Does Hot Water Save Water?
It potentially can in applications where heat materially improves cleaning performance, but it would be wrong to claim that hot water always reduces water consumption.
Hot water can be particularly effective against:
- Grease
- Oil
- Oily grime
If heat allows the contamination to be removed faster, the machine may require less operating time.
But actual water consumption depends on the specific machine and cleaning process.
Hot-water machines also have other operating requirements that need to be considered.
For more information, read:
Hot vs Cold Water Pressure Washers: Which Do You Need?
Does Detergent Reduce Water Consumption?
Again, potentially — but not automatically.
An appropriate detergent can loosen soils and make them easier to remove.
That may reduce the amount of pressure washing required for some tasks.
But effectiveness depends on:
- Correct chemical selection
- Dilution
- Application
- Contact time
- Temperature
- Surface
- Contamination
The best approach is to develop an efficient cleaning process, rather than assuming more chemical or more pressure will automatically save water.
Pressure Washing and Sustainability
For businesses trying to reduce environmental impact, water consumption is worth considering.
But sustainability shouldn't be reduced to a single number.
A cleaning process can involve:
- Water
- Electricity
- Fuel
- Detergent
- Labour
- Equipment
- Wastewater
The objective should be to achieve the required cleaning result efficiently while avoiding unnecessary consumption.
A pressure washer that uses slightly more water per minute but completes a job substantially faster could potentially be more efficient overall.
Conversely, using excessive pressure, flow or cleaning time when it isn't needed wastes resources.
Where Does Pressure Washer Wastewater Go?
This is an important consideration, particularly for commercial and industrial users.
Pressure washing doesn't make contamination disappear.
It moves it.
Wastewater may contain:
- Dirt
- Detergent
- Oil
- Grease
- Chemicals
- Other contaminants
Businesses should consider where that wastewater is going and comply with applicable local requirements.
Don't automatically assume pressure-washing runoff can simply enter a stormwater drain.
This becomes particularly important when cleaning workshops, machinery, vehicles and industrial sites.
Don't Use More Water Than the Job Requires
A larger professional pressure washer can be extremely productive, but that doesn't mean maximum output should be used for every job.
Match the cleaning process to the task.
A small area with light contamination may require a different approach from:
a muddy excavator
or:
a large commercial yard.
Efficient cleaning is about using enough pressure, flow, heat and chemistry — not necessarily the maximum available.
Water Supply Requirements
Before purchasing a commercial pressure washer, make sure the intended site can supply sufficient water.
A machine capable of delivering a particular flow needs an adequate incoming water supply.
If the supply can't keep up with the machine's requirements, performance may be affected and the equipment may not operate as intended.
Check the manufacturer's requirements for:
- Water supply
- Inlet pressure
- Inlet flow
- Maximum inlet temperature
- Hose requirements
This is particularly important with higher-flow commercial machines.
Choosing a Water-Efficient Commercial Pressure Washer
Don't simply look for the machine with the lowest L/h specification.
Instead, ask:
- What am I cleaning?
- How much contamination needs removing?
- What pressure is appropriate?
- What water flow provides good productivity?
- How long will the cleaning job take?
- Would detergent improve efficiency?
- Would hot water improve grease removal?
- What water supply is available?
- Where will the wastewater go?
- What is the total cost per completed cleaning job?
Those questions provide a much better basis for choosing commercial equipment.
Nilfisk Commercial Pressure Washers
Hygiene Direct supplies professional Nilfisk water blasters and pressure washers throughout New Zealand.
Different Nilfisk machines provide different combinations of:
- Pressure
- Water flow
- Portability
- Hose length
- Temperature
- Professional duty
That allows businesses to choose a machine appropriate to the cleaning task rather than simply selecting the highest-pressure or lowest-flow option.
Browse:
Commercial Water Blasters & Pressure Washers
So, How Much Water Does a Pressure Washer Use?
It depends on the machine.
Check its litres-per-hour specification and divide by 60 if you want an approximate litres-per-minute figure.
But for commercial buyers, the more useful question is often:
How much water, labour and time will this machine require to complete my cleaning job?
Don't assume the lowest L/h figure automatically means the most water-efficient machine.
The ideal pressure washer is one that provides the appropriate combination of:
Pressure + water flow + cleaning performance + operating time
for your application.
If you're choosing equipment, start with our How to Choose a Commercial Water Blaster: NZ Buying Guide, or explore Hygiene Direct's Commercial Water Blasters & Pressure Washers.
For practical advice, contact your local Hygiene Direct branch.
He Waka Eke Noa – We Are All in This Canoe Together.
Frequently Asked Questions
How much water does a pressure washer use per minute?
Divide the machine's litres-per-hour flow by 60. For example, 600 L/h equals approximately 10 litres per minute at the stated flow.
How much water does a pressure washer use in 30 minutes?
A machine operating continuously at 600 L/h would theoretically use approximately 300 litres in 30 minutes. Actual use depends on how the machine is operated.
Does a pressure washer use less water than a hose?
It can, depending on the flow rates and how quickly each method completes the cleaning task. There isn't one universal percentage that applies to every hose and pressure washer.
Is a lower L/h pressure washer more water efficient?
Not necessarily. A higher-flow machine may complete some cleaning tasks faster. Water consumption per completed job can therefore be more meaningful than flow per hour alone.
Does higher PSI use more water?
Not necessarily. PSI measures pressure while L/h measures water flow. They are separate specifications.
How much water does a 600 L/h pressure washer use per minute?
Approximately 10 litres per minute at the stated flow.
How much water does a 520 L/h water blaster use per minute?
Approximately 8.7 litres per minute at the stated flow.
How can I reduce water use when pressure washing?
Use equipment appropriate for the job, select the correct nozzle, maintain the machine, use suitable cleaning chemistry where appropriate and clean systematically to avoid unnecessary repeat passes.
Where can I buy a commercial pressure washer in NZ?
Hygiene Direct supplies commercial water blasters and Nilfisk pressure washers throughout New Zealand.
Related Water Blaster & Pressure Washer Guides
- How to Choose a Commercial Water Blaster: NZ Buying Guide
- Water Blaster vs Pressure Washer: Is There a Difference?
- Hot vs Cold Water Pressure Washers: Which Do You Need?
- What PSI Water Blaster Do I Need?
- Commercial vs Domestic Water Blasters
- Best Water Blaster for Commercial Cleaning
- How to Clean Concrete With a Water Blaster
- Pressure Washer Maintenance Guide
- Nilfisk Water Blasters: Choosing the Right Model