Pressure Washer Troubleshooting Guide – Common Problems and How to Fix Them
A pressure washer is one of the most useful tools for cleaning patios, driveways, decking, vehicles and outdoor furniture. However, like any machine, it can occasionally develop faults that affect its performance.
Whether your pressure washer won't start, has low pressure, is leaking water or keeps pulsing, many common problems can be diagnosed and repaired without replacing the entire machine.
This guide brings together the most common pressure washer faults and links to detailed troubleshooting, repair, maintenance and buying guides to help you keep your pressure washer working at its best.
Most Popular Pressure Washer Problems
If you're not sure where to start, these are the faults we see most often:
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Pressure Washer Won't Start?
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Pressure Washer Has Low Pressure?
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Pressure Washer Pulsing or Surging?
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Pressure Washer Leaking Water?
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Pressure Washer Won't Build Pressure?
Each guide explains the likely causes, how to diagnose the problem and the replacement parts that may be needed.
Starting Problems
Pressure Washer Won't Start
If your pressure washer won't switch on, the cause is often something simple.
Common causes include:
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No electrical power
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Tripped circuit breaker
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Overheated motor
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Blocked inlet filter
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Air trapped in the pump
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Faulty switch
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Petrol engine problems
Read our guide: Pressure Washer Won't Start? Causes and How to Fix It
Pressure Washer Starts Then Stops
If your machine starts normally but cuts out after a short time, the fault is often related to overheating or restricted water flow.
Common causes include:
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Thermal cut-out
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Low water supply
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Airlock
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Blocked nozzle
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Pressure relief valve
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Fuel problems (petrol models)
Read our guide: Pressure Washer Starts Then Stops? Causes and How to Fix It
Pressure Problems
Pressure Washer Has Low Pressure
Low pressure is one of the most common complaints.
Typical causes include:
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Blocked nozzle
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Dirty inlet filter
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Worn O-rings
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Leaking hose
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Faulty trigger gun
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Pump wear
Read our guide: Pressure Washer Has Low Pressure? Causes and How to Fix It
Pressure Washer Won't Build Pressure
If water flows through the machine but there is little or no cleaning power, pressure is failing to build correctly.
Common causes include:
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Air trapped inside the pump
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Blocked spray nozzle
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Pressure relief valve problems
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Worn pump seals
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Pump valve wear
Read our guide: Pressure Washer Won't Build Pressure? Causes and How to Fix It
Pressure Washer Pulsing or Surging
Pressure that repeatedly rises and falls is usually caused by water flow or pressure regulation problems.
Common causes include:
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Airlocks
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Blocked inlet filter
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Worn O-rings
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Blocked nozzle
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Pressure relief valve
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Pump valve wear
Read our guide: Pressure Washer Pulsing or Surging? Causes and How to Fix It
Water Leaks
Pressure Washer Leaking Water
Water leaks should never be ignored, as they often become worse over time.
Common causes include:
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Damaged hose
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Worn O-rings
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Loose fittings
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Cracked lance
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Trigger gun leaks
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Pump seal failure
Read our guide: Pressure Washer Leaking Water? Causes and How to Fix It
Unusual Noises
Pressure Washer Making a Loud Noise
A whining, grinding or rattling pressure washer is usually warning you that something needs attention.
Common causes include:
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Air inside the pump
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Pump cavitation
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Blocked filter
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Bearing wear
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Loose components
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Pump damage
Read our guide: Pressure Washer Making a Loud Noise? Causes and How to Fix It
Step-by-Step Repair Guides
If you've identified the fault, these guides explain how to carry out some of the most common repairs.
Each guide includes step-by-step instructions and advice to help you complete the repair safely.
Pressure Washer Buying Guides
Choosing the correct replacement parts is just as important as diagnosing the fault.
Our buying guides include:
These guides explain compatibility, connection types and how to choose the correct replacement parts for your machine.
Pressure Washer Maintenance Guides
Regular maintenance helps prevent many common faults before they occur.
Our maintenance guides include:
Following these simple maintenance tips can help extend the life of your pressure washer and reduce repair costs.
Common Pressure Washer Parts That May Need Replacing
Many faults can be resolved by replacing a worn component rather than replacing the entire pressure washer.
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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Spray nozzles
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Turbo nozzles
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Foam lances
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O-rings
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Seal kits
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Water inlet filters
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Pressure relief valves
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Pump valve kits
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Adaptors and connectors
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Extension wands
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Surface cleaners
Choosing the correct replacement parts helps restore cleaning performance while extending the life of your machine.
You can find replacement pressure washer parts and accessories for many popular brands, including Kärcher, Nilfisk, Bosch, Makita and more, from Yourspares.
Pressure Washer Maintenance Checklist
Before Every Use
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Check the high-pressure hose for damage.
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Inspect O-rings and connectors.
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Clean the water inlet filter if required.
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Check the spray nozzle is clear.
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Ensure all fittings are secure.
After Every Use
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Flush the machine with clean water.
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Drain water from the hose and lance.
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Release any remaining pressure.
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Inspect for leaks.
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Store accessories safely.
Before Winter Storage
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Drain all water from the machine.
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Clean the inlet filter.
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Inspect hoses and seals.
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Store indoors in a frost-free location.
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Consider using a suitable pump protector if recommended by the manufacturer.
Final Thoughts
Most pressure washer faults are caused by blocked nozzles, worn seals, damaged hoses or restricted water flow rather than major mechanical failures.
By carrying out regular maintenance, replacing worn components when necessary and following the troubleshooting guides above, you can restore cleaning performance, prevent more expensive repairs and significantly extend the life of your pressure washer.
Whether you're dealing with low pressure, leaks, pulsing or starting problems, the guides in this hub will help you identify the cause and get your pressure washer back to working at its best.
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