How to Winterise Your Pressure Washer
When the colder months arrive, it's important to prepare your pressure washer for storage. Water left inside the pump, hoses or accessories can freeze during winter, expanding as it turns to ice and causing expensive damage to internal components.
Every year, many pressure washers require replacement pumps, seals and connectors simply because they weren't properly winterised before being put away.
Fortunately, winterising a pressure washer only takes a few minutes and can significantly extend the life of your machine.
In this guide, we'll explain how to winterise your pressure washer correctly and protect it from frost damage.
Why Winterising Is Important
Unlike many garden tools, a pressure washer contains water inside:
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The pump
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High-pressure hose
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Trigger gun
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Spray lance
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Internal pipework
Even a small amount of frozen water can crack plastic or aluminium components.
Repairing frost damage is often far more expensive than taking a few minutes to prepare the machine for storage.
Before You Start
Electric Pressure Washers
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Switch the machine off.
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Disconnect it from the mains supply.
Petrol Pressure Washers
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Stop the engine.
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Allow it to cool completely.
Step 1 – Disconnect the Water Supply
Turn off the garden tap.
Disconnect the garden hose from the pressure washer.
Allow any remaining water to drain naturally.
Step 2 – Release the Pressure
Squeeze the trigger gun after disconnecting the water supply.
This helps remove trapped pressure from the system.
Continue until water stops flowing.
Step 3 – Drain the High-Pressure Hose
Disconnect the high-pressure hose.
Hold one end higher than the other and allow all water to drain out.
Coil the hose loosely once empty.
Step 4 – Empty the Spray Lance
Remove the spray lance.
Hold it upright and allow any remaining water to drain.
If possible, remove any detachable nozzles and dry them separately.
Step 5 – Drain the Pump
The pump is the most important component to protect.
With the water supply disconnected:
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Hold the trigger open.
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Briefly switch the pressure washer on for one or two seconds only, if recommended by the manufacturer, to help expel any remaining water from the pump.
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Switch it off immediately.
Do not allow the pump to run dry for more than a second or two, as this can cause damage.
If your manufacturer's instructions advise a different draining method, always follow those recommendations.
Step 6 – Inspect the Machine
Before storing the pressure washer, inspect:
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High-pressure hose
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Trigger gun
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Spray lance
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Nozzles
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O-rings
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Water inlet filter
Replacing worn parts now means the machine will be ready to use when warmer weather returns.
Step 7 – Clean the Inlet Filter
Remove the water inlet filter.
Wash away:
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Dirt
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Sand
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Leaves
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Small stones
Allow it to dry before refitting.
Step 8 – Store Accessories Properly
Store:
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Hoses
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Lances
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Trigger guns
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Nozzles
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Foam lances
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Brushes
Keep accessories together in a clean, dry location to prevent damage or loss.
Step 9 – Store the Pressure Washer Indoors
Whenever possible, store your pressure washer in:
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A garage
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A shed
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A utility room
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A dry workshop
The storage area should remain frost-free throughout winter.
What Happens If You Don't Winterise?
Leaving water inside the machine can lead to:
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Cracked pump housing
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Split hoses
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Damaged trigger guns
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Broken lances
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Leaking seals
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Pump failure
Many of these faults only become apparent when the pressure washer is used again in spring.
Should You Use Pump Protector?
Some manufacturers recommend using a pump protector or antifreeze solution specifically designed for pressure washers.
These products can:
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Help protect internal seals
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Reduce corrosion
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Prevent freezing inside the pump
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Extend pump life
Always use products recommended for pressure washer maintenance.
Common Winter Storage Mistakes
Leaving Water in the Hose
Even if the machine has been drained, water trapped inside the hose can freeze and damage it.
Always drain hoses completely.
Storing Outdoors
A waterproof cover does not protect against freezing temperatures.
Store the pressure washer indoors whenever possible.
Forgetting the Accessories
Nozzles, lances and trigger guns can also retain water.
Drain and dry them before storage.
Ignoring Worn Seals
Winter is the perfect time to replace worn O-rings and seals ready for the next cleaning season.
Getting Your Pressure Washer Ready for Spring
Before using the pressure washer again:
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Inspect hoses.
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Check O-rings.
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Clean the inlet filter.
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Inspect the nozzle.
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Check all connections for leaks.
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Test the machine using clean water.
A quick inspection can prevent problems when you first use it.
How This Relates to Other Pressure Washer Problems
Correct winter storage helps prevent many common faults.
For example:
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If your pressure washer is leaking water, see Pressure Washer Leaking Water? Causes and Fixes
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If the machine won't build pressure, read Pressure Washer Won't Build Pressure? Causes and Fixes
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If pressure is low, see Pressure Washer Has Low Pressure? Causes and Fixes
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If your machine won't start after storage, read Pressure Washer Won't Start? Causes and Fixes
Replacement Parts After Winter
If your pressure washer has suffered frost damage, common replacement parts include:
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High-pressure hoses
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Spray lances
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Trigger guns
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O-rings
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Seal kits
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Water inlet filters
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Pump components
Replacing damaged parts promptly can often restore the machine without the need for a complete replacement.
You can find replacement pressure washer parts and accessories for many popular brands, including Kärcher, Nilfisk, Bosch, Makita and more, from Yourspares.
Final Thoughts
Taking a few minutes to winterise your pressure washer can help prevent expensive frost damage and ensure it's ready to use when spring arrives.
By draining all water from the machine, inspecting key components and storing it in a dry, frost-free location, you can extend the life of your pressure washer and avoid many common repair issues.
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