Common Pressure Washer Problems and Easy Fixes
Most pressure washer problems trace back to airflow, a clog or a worn seal. Low or pulsing pressure usually means air in the system or a blocked nozzle. Leaks point to loose connections or perished O-rings, and a machine that will not start needs power or fuel checks. Many faults are simple fixes, not a reason to replace the tool.
A pressure washer that suddenly misbehaves can feel like a breakdown, but the common problems are usually easy to diagnose. More often than not the machine is fine, and the fault is trapped air, a clogged tip or a tired seal that costs very little to sort out.
Below are the issues owners run into most, with practical fixes for each. If you are newer to the machine, our guide on how to use a pressure washer safely is a useful companion, since technique prevents many faults in the first place.
Low or no pressure
Weak pressure is the most common complaint, and it is nearly always about water in or air out. Start by confirming the water supply is fully on and the inlet filter is clean, because the pump needs a strong, steady feed to build pressure.
- Turn the tap fully on and check the hose is not kinked or too narrow.
- Clean the inlet screen or filter, which traps grit and starves the pump.
- Clear the nozzle with a pin or the cleaning tool, as a partial blockage kills pressure.
- Bleed trapped air by running water through with the trigger held open before starting.
If pressure is still low after those checks, a worn nozzle or a tired pump seal may be the cause, both of which are inexpensive parts on many machines.
Pressure surges or pulses
A washer that pulses, throbbing strong then weak, is usually fighting a blockage or an air pocket. The most frequent cause is a partly clogged nozzle, which lets pressure build and release in waves rather than a steady stream.
Clear the nozzle first, then check the inlet filter and make sure the water supply keeps up with the machine. Air trapped in the pump can also cause surging, so run water through with the trigger open to purge it. Using the wrong tip for the job contributes too, a theme we touch on in how to choose a pressure washer.
Machine will not start
A washer that stays silent needs a quick, methodical check. The steps differ a little between electric and gas, but both start with the basics rather than assuming the worst.
On an electric model, confirm it is plugged into a working, protected outlet, check the reset button on the plug or cord has not tripped, and inspect the lead for damage. Many electric washers also refuse to run if the trigger is not pressed to prime them. On a gas model, check the fuel level, the choke position, the oil level, which some engines sense before starting, and the spark plug. Working through these in order usually finds the fault.
Leaks from hoses or connections
Small leaks are common and rarely serious. Most drips come from loose fittings or worn rubber O-rings at the connection points, both of which are quick and cheap to fix once you find the source.
Hand tighten every connection first, since many leaks simply stop there. If a joint still weeps, replace the small O-ring inside it, as these harden and crack with age. A hose that leaks along its length rather than at the ends has usually split and should be replaced, because a damaged high pressure hose is a safety risk.
Detergent will not draw or spray
If soap will not come through, the machine is almost always still in high pressure mode. Detergent only siphons at low pressure, so you must fit the soap nozzle or switch to the low pressure setting for it to draw properly.
- Fit the black soap tip or select the low pressure setting, as high pressure blocks the siphon.
- Check the detergent tube and filter are clean and pushed fully into the soap.
- Use a thin, pressure washer safe detergent, since thick cleaners can clog the pickup.
Once the soap is applied at low pressure, switch back to a rinsing tip to wash it off. Getting this sequence right makes cleaning cars and siding far easier, as covered in what you can clean with a pressure washer.
When to repair and when to replace
Nozzles, O-rings, filters and hoses are wear items, and replacing them is normal and usually cheap. If the pump and motor or engine are sound, fresh seals and a clean filter can give the machine years more service for very little outlay.
Consider replacing the whole washer when the pump is failing, the motor or engine is worn, or repairs would cost close to a new unit. If yours is on its way out, our roundup of the best pressure washers can help you choose a reliable replacement, and you can find more fixes and care tips in our Outdoors & Garden guides.
Ready to pick one?
If a repair no longer makes sense, our top picks cover dependable washers for every kind of job.
Frequently asked questions
Why is my pressure washer losing pressure?
Usually the water feed is restricted or a nozzle or filter is clogged. Check the tap is fully on, the hose is not kinked, and the inlet screen is clean, then clear the nozzle. Worn seals or a tired pump can cause it too.
Why does my pressure washer pulse?
Pulsing normally means a partly blocked nozzle or trapped air. Clear the tip, clean the inlet filter, and run water through with the trigger open to purge air. Make sure the water supply keeps up with the machine as well.
Why will my pressure washer not start?
On electric models, check the outlet, the reset button and whether the trigger needs pressing to prime it. On gas models, check fuel, oil, the choke and the spark plug. Working through the basics in order usually finds the cause.
Why is my detergent not spraying?
Detergent only draws at low pressure, so fit the soap nozzle or switch to the low pressure setting. Check the pickup tube and filter are clean and seated, and use a thin, pressure washer safe soap rather than a thick cleaner.
How do I stop my pressure washer leaking?
Hand tighten every connection first, as that fixes most drips. If a joint still weeps, replace the small O-ring inside it. A hose leaking along its length has split and should be replaced for safety.
Is it worth repairing a pressure washer?
Often yes. Nozzles, seals, filters and hoses are cheap and easy to replace. If the pump and motor are sound, these fixes restore the machine. Replace the whole unit only when the pump or engine is worn or repairs near the cost of new.
