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What To Do When Your Pressure Washer Loses Pressure

When you're in the middle of pressure washing, discovering that your water pressure is losing pressure can complicate your day. Troubleshooting issues often only requires some patience while methodically checking common problem areas.

You may be able to resolve the situation with a slight adjustment instead of a costly fix or replacement. Check out the most common culprits.

Low Pressure on Pressure Washer

A loss of pressure could be due to issues at the water source. Start by checking the water flow, which should never fall below what your washer requires for operation. The typical range may be as low as 2 gallons per minute for smaller machines and as high as 10 GPM for industrial-strength units. Check the user's manual to determine the correct level. You should ensure the water temperature is optimal for the machine. While this might not seem important, the wrong temperature can diminish performance and cause problems in pressure.

Pressure Washer Nozzles and Wands

Low pressure on a pressure washer could be a blockage in the nozzle. Try running water through an unconnected nozzle to check the flow. You can also shine a light through the nozzle to discover an obstruction.

You may be able to clear the stoppage with an air compressor blast or a small tool like a paper clip. If your nozzle has a designated device specifically for cleaning and maintenance, use that tool to prevent damage to components.

You can also check for broken or worn-out O-rings in a wand or gun. Remove the outlet coupler and inspect the plunger. Look for signs of oxidation, such as excessive discoloration or rust particles.

Using the wrong nozzle or a broken tip is another possibility. If you're using a green 25-degree tip instead of a black soap injector tip, that could explain why your machine isn't performing correctly.

Water pressure nozzles and guns do much of the work and can quickly wear out over time. Check which tips are compatible with your unit, and replace worn-out nozzles. A good time to consider replacing nozzles is when your machine's operating pressure drops 10% from normal.


Check for any leaks in your hoses or kinks in the line. Old or broken hoses are likely to get leaks or cracks and may need replacement. A reel for your new hose keeps the equipment in good working condition. Verify that your hoses are the correct size. Pipes that are too narrow can quickly fail. Those that are too wide can't deliver enough pressure.

If you only have a damaged section or two, you may be able to repair them by cutting out the cracked pieces and connecting the remaining sections with couplers and tightening clamps. If you only have a blockage or obstruction in the hose, try cleaning or unclogging it first.

Pressure Washing Machine Maintenance

Various situations inside your unit can create a pressure problem, especially for gas-powered units that require more maintenance than electric ones. Stay on top of the following maintenance items and double-check them if pressure dips precipitously.

Replace Gas Seasonally

Old fuel can create an issue. To prevent this from happening, ensure that you replace your gas at least every three months to help your machine run smoothly.

Check the Oil

Regularly check the oil in your machine according to the manufacturer's specifications. Running with old or low-oil can ruin components inside the engine. Check your owner's manual for instructions on how often to replace the oil and what grade to use.

Check the Spark Plugs

If your spark plugs misfire, cleaning them doesn't always do the trick. They typically need replacing every six months or after 100 hours of operation.

Clean or Replace the Air Filter

A dirty air filter can prevent any engine from functioning well. Ensure yours is clean before attempting further diagnosis or repair work on the unit itself. If you have a reusable foam filter, simply wash it gently, let it dry, and reinstall it. Replace torn or excessively dirty paper filters. Check that none of the housing around the filter allows debris into the system.

Check for a Slipping Belt

If you own a gas-powered washer, one of the first things you should do is check for belt slipping. Ensure the correct belt is on the machine, and try to tighten it. If you can't tighten it securely, you may need to replace it. Installing a new belt can be difficult and time-consuming, so if you are not confident enough to do this yourself, seek the help of a technician instead.

Check Your Unloader Valve

The unloader valve regulates water flow depending on whether or not you pressurize the trigger handle. Open the valve and check to see if it needs any adjustments. For example, a rusty spring might need replacing.

Test if the valve only needs adjusting by operating the unit and monitoring the pressure. Turn the knob slowly, and run the machine again to see if the pressure rises. Adjust the setting gradually to determine if you can reach the desired operating pressure.

Bad Water Pump or Accessories

Water pumps are another component doing a lot of work, so they may fail from time to time. Check accessories around the pump, such as a clogged inlet filter or inlet suction strainer. You may simply need to clean or replace these parts.

Inspect the system for airtightness by reviewing all connections and fittings for leaks or imperfections. You may have air in the system. Figure out if you can purge excess air by filling up the unit with water through the inlet hose while it is off and pressing the trigger to let the water push any bubbles out of the system.

If all else fails, the time may come for a new pump. Pay close attention when selecting the correct model. Never purchase an oversized or overpowered pump. Choose one with the proper fit for your machine.

Regular Upkeep With High-Quality Parts

These are the most common ways to isolate the reasons behind low pressure on a pressure washer, and they can often lead to a solution. Replacing a piece or part can be much more efficient than buying a new machine prematurely. Whatever your pressure washer needs, head to PW Outlet for repair parts or a new unit when you're ready.