How to Maintain a Pressure Washer

If you want your pressure washer to last for years (and actually work when you need it), a little regular maintenance goes a long way. To maintain your pressure washer, you just need to adopt a few simple habits, such as checking the oil, cleaning filters, replacing worn nozzles, and flushing out leftover detergent.

Proper pressure washer maintenance means it’ll run stronger, last longer, and stay safe to use. In this guide, you’ll learn exactly what to check, clean, and replace — without needing to be a mechanic.

Supplies Needed

Let’s start with what you’ll need. You don’t have to buy everything right away, but having these on hand will make your maintenance routine easier:

Tools

• Ratchet
• Spark plug socket
• Spark plug gap tool (or feeler gauge)
• Optional spark plug wrench (makes spark plug work easier)
• Cleaning needle or thin wire (for nozzle cleaning; often included with the washer)
• Soft brush or dry cloth (for vents and exterior cleaning)
• Container or pan (for used oil and draining fuel)
• Screwdriver or wrench set (for removing covers or filters)

Materials

• Engine oil (check your manual for the right type)
• Replacement air filter
• Replacement spark plug
• O-rings (used to seal connections; you may need spares)
• Fuel stabilizer (for gas models, especially before storage)
• Antifreeze (glycol-based, for winterizing in cold climates)
• Fittings grease (for filter and seal lubrication)
• Replacement nozzles (in case of clogging or wear)
• Garden hose (standard but necessary for flushing and cleaning)
• Breathable cover (for long-term storage)

Optional but Useful

• Short hose (for antifreeze application during winterization)
• Pre-mixed or ethanol-free fuel (for optimal gas engine performance)
• Safety gloves and protective eyewear (recommended during maintenance)

Important: Always check your owner’s manual for your exact model. It will tell you the right part numbers, oil type, and how often to do each maintenance step.

Maintenance Before Using a Pressure Washer

Before you fire up your pressure washer, here’s a checklist to follow every time, especially if it’s been sitting for a while:

1. Check Fluid Levels

For gas models, check both the oil and fuel levels. Make sure your gas is fresh as gasoline over 30 days old can gum up the carburetor. However, don’t overfill.

For electric models, you can skip this, but still check for water leaks.

2. Inspect Screens and Filters

Look at the water inlet screen (where your garden hose connects) and the inline wand screen (inside the spray wand). If they’re clogged with dirt or grit, clean them or replace them. A clogged screen can silently strangle your pressure and damage the pump.

For tips that will further avoid damage, read: Pressure Washer Safety Tips to Avoid Injury and Damage. 

3. Check the Spray Gun and Hose

Inspect the hose for leaks, bulges, or worn areas. Make sure all connections are tight. Squeeze the spray gun trigger to test if it moves smoothly and the safety lock works. Even a minor leak at full pressure can cause a serious spray hazard.

4. Inspect the Detergent System

If you’re using soap or detergent, check the siphoning tube and its small filter. Make sure they’re clean, so detergent can flow properly.

5. Flush the Garden Hose

Run water through your hose before connecting it. You’d be surprised how often spiders, leaves, or grit block the flow. Even small bits of debris can damage the pump or reduce water pressure and lead to performance issues that are hard to trace later on.

Reminder for gas models: Never run them indoors. They give off carbon monoxide, which is dangerous. Reminder for electric models: Keep the plug and cord dry; never touch them with wet hands.

Maintenance After Using a Pressure Washer

When you’re done cleaning, you can’t just turn it off and walk away. Follow these steps to avoid damage or clogs:

1. Clean the Detergent System

If you used soap, rinse it out by running clean water through the system for 1–2 minutes. This prevents leftover soap from hardening or clogging the tubes.

2. Relieve Pressure

Turn off the machine and water supply. Unplug the unit if it’s electric. Squeeze the spray gun trigger until no more water comes out — this releases built-up pressure. Lock the trigger in the safety position. Let the machine cool down before storing it.

3. Drain Excess Water

Disconnect the hoses and wand. Follow your manual’s instructions to drain any remaining water from the pump. Wipe down the body to remove any grime or mud so it’s clean for next time.

Regular Maintenance Schedule

To keep your pressure washer in top shape, follow this timeline:

At Every Use

• Check the hose, spray gun, power cord (electric models), and all connections. Look for cracks, leaks, or damage.
• Check the water and detergent filters for dirt or blockages.
• Check the oil level (for gas models).

Every Month

• Clean water and detergent filters.
• Clean nozzles using the supplied cleaning needle. If cleaning doesn’t help, replace them.
• Check the oil level.

Every 3 Months or After 200 Hours of Use

• Have a technician inspect the hydraulic circuit, pump oil, pump attachments, filters, and nozzles.

Every 6 Months or After 500 Hours of Use

• Have a technician check the suction and delivery valves and the unloader valve.
• Replace pump oil, filters, and nozzles.

How to Maintain Gas vs Electric Pressure Washers

Gas-Powered Pressure Washer Maintenance

Gas engines need a bit more care. My colleague’s father, Frank, has used a gas-powered pressure washer for over two decades, and shares a key reminder for maintenance: “Check the manual for how to overwinter your pump and gas. If the pump is not going to be run, gas should either be drained or will need to have a stabilizer added.”

Here’s what to do regularly:

• Change the engine oil: After warming up the engine, drain the old oil into a pan. Refill with fresh oil (check your manual for the right type and amount). Never overfill. Take the used oil to a recycling center.
• Check the spark plug: Clean around the spark plug before removing it. Check for cracks or burn marks. Replace it if it looks damaged. Before reinstalling, check the gap between the electrodes with a gauge to make sure it’s correct.
• Check the air filter: Clean or replace the air filter. Foam filters can be washed and reused; paper filters need to be replaced if they’re dirty.
• Maintain the fuel system: Use fresh gasoline (less than 30 days old). Consider using ethanol-free or pre-mixed fuel. If storing the washer for a while, use a fuel stabilizer to prevent corrosion.

Safety Tip: Always disconnect the spark plug wire before doing maintenance.

Electric Pressure Washer Maintenance

Electric models are simpler but still need attention. As Frank puts it, “Electric models are better for light-duty work or people who don’t want to deal with gas or oil. They’re generally not as sturdy and usually operate at a lower PSI.”

As they may not be as sturdy as gas-powered washers, they also need to be maintained: 

• Keep cords dry and check for damage.
• Check water inlet screens and filters for blockages.
• Clean nozzles and spray tips after each use.
• Inspect the spray gun, wand, and hoses for cracks or leaks.

Component-Specific Maintenance

Beyond basic checks, there are small parts of your pressure washer that need regular attention. Ignoring these can lead to loss of pressure, leaks, or even pump damage. They’re easy to take care of if you know what to do.

Cleaning the Water Inlet Screen

This little mesh screen keeps debris from getting into your pump. Here’s how to clean it:

1. Unscrew the water connection nozzle (where you attach the garden hose).
2. Carefully pull out the inlet screen.
3. Rinse it under clean, running water to remove dirt and grit.
4. Reinsert the screen and screw the nozzle back on by hand (don’t overtighten).

Tip: If you notice holes or tears in the screen, replace it. A damaged screen won’t protect your pump.

Cleaning the Water Filter (If Your Model Has One)

Some pressure washers have an additional water filter to guard against dirty water:

1. Disassemble the filter following your manual.
2. Rinse all parts under running water until clean.
3. Apply grease to the seals to keep them soft and leak-free.
4. Reassemble carefully, making sure all seals are seated properly.

Clearing Spray Tip and Nozzle Clogs

Over time, tiny bits of dirt can clog the nozzle, causing pressure loss or uneven spray. Here’s how to fix it:

1. Turn off the machine and disconnect it from power (or disconnect the spark plug wire on gas models).
2. Use the supplied cleaning needle or a thin piece of wire to gently poke through the nozzle opening.
3. Rinse the nozzle under running water to flush out debris.
4. Reinstall and test the spray pattern.

Tip: If cleaning doesn’t fix the spray, replace the nozzle because they’re inexpensive and easy to change.

Lubricating Hose, Spray Gun, and Wand Connections

These connections have O-rings that need to stay lubricated to seal properly:

1. Apply a small amount of silicone-based lubricant (never petroleum-based) to the O-rings and threads.
2. Wipe off any excess to avoid attracting dirt.
3. Check the O-rings for wear. Replace them if they’re cracked or flattened.

Inspecting Muffler and Spark Arrestor (Gas Models Only)

If your gas pressure washer has a muffler or spark arrestor, it’s important to keep these clean and clear:

1. Make sure the engine is off and cool.
2. Follow your manual’s instructions to access the muffler and/or spark arrestor.
3. Check for carbon buildup or blockage. Clean gently if needed or replace worn parts.

Cleaning Cooling Vents (Gas Models Only)

Cooling vents allow the gas engine to breathe and prevent overheating:

1. Use a soft brush or dry cloth to clear away dust, grass, and dirt from the cooling fins and vent openings.
2. Never block these vents during operation, as good airflow is essential.

Replacing Worn O-Rings

O-rings seal the connections at the water inlet, high-pressure hose, spray gun, and wand. Over time, they can crack or flatten:

1. Regularly inspect all O-rings for damage.
2. Replace any that look worn or damaged (many pressure washer kits come with spare O-rings, or you can buy them separately).
3. Lubricate new O-rings lightly before installation.

Long-Term Storage and How to Winterize Your Pressure Washer

If you’re storing your pressure washer for more than 30 days — or getting ready for winter — here’s what to do:

• Perform your usual after-use maintenance (flush detergent, drain water, clean machine).
• Gas models: Follow Frank’s advice and check your manual. If you didn’t add fuel stabilizer, drain the gas tank and run the engine until it’s dry. Store leftover fuel safely.
• Change the engine oil and briefly start the engine to circulate the fresh oil.
• Flush the pump to clear out old water.
• Protect from freezing: If you can’t store the washer in a frost-free place, run antifreeze through the system to prevent internal damage (see below).
• Store properly: Keep the machine in a dry, protected spot away from heat, moisture, or freezing temperatures. Cover it with a breathable (not plastic) cover.

Winterizing with Antifreeze (If Storing in Cold Climates)

If you can’t store your washer in a warm, frost-free place, you’ll need to run antifreeze through it to protect the pump and seals. Here’s a quick guide:

1. Remove the spray lance and connect a short water hose.
2. Mix glycol-based antifreeze following the instructions and pour it into a clean container.
3. Dip the hose into the antifreeze.
4. Hold the spray gun lever and switch on the machine; let it run until antifreeze sprays through.
5. Press and release the spray gun trigger several times.
6. Switch off the machine, unplug it, and dismantle the spray gun and hose.
7. Let the antifreeze drain back into the container for reuse or dispose of it following local rules.

Final Tip: Check nozzles, hoses, and lances for damage before storing long-term, and make sure everything is dry and clean.

FAQ

TLC for Your Pressure Washer

Just like any hardworking tool, your pressure washer needs a little TLC to perform at its best.  By staying on top of simple tasks like changing oil, cleaning filters, and checking for wear and tear, you’ll keep your washer running smoothly and ready to handle whatever mess comes its way.

Think of it like regular car maintenance — you wouldn’t skip an oil change, and you shouldn’t skip your pressure washer’s upkeep either.

Home Gnome delivers the best home service experience at the click of a button. Book reliable, skilled services in seconds and leave the rest to us.

Main Photo Credit: Animaflora PicsStock / Adobe Stock