Winterizing your pressure washer isn’t complicated, but skipping this essential maintenance can be costly. Drain all the water, add pump antifreeze, protect the engine, and store properly. This simple prep prevents freeze damage that cracks pumps and turns a $20 maintenance job into a $300 repair headache.
When asked about winterization mistakes he sees homeowners make, Kenneth Hinton from Ken’s Mobile Service said: “The most common issue is most homeowners don’t winterize any of the equipment, period. I see more equipment failures from improper storage than from actual wear and tear. A quick inspection before winterization saves clients hundreds in spring repairs.”
| Project Cost: $20 – $50 Time needed: 30 minutes to 1 hour Difficulty: Easy |
What you’ll need
- Pump antifreeze OR commercial pump saver (like Simpson Universal pressure washer pump guard)
- Clean water for flushing system
For Gas Models:
- Fuel stabilizer OR fuel drain container
- Fresh engine oil
- Basic tools for oil change
Optional but Recommended:
- White vinegar (for DIY cleaning solution)
- WD-40 spray (helps remove remaining water and lubricates O-rings)
- New spark plug (if needed)
Step 1: Clean and inspect your pressure washer
Start by giving your detergent system a good flush with clean water. Run it on low pressure for 1 to 2 minutes until the water runs clear. Pull out those pump filters and strainer screens (they’re debris magnets), rinse thoroughly, and replace any questionable ones now rather than dealing with spring startup headaches.
Your nozzles need some love, too. Soak them in a 50/50 vinegar solution for at least 15 minutes to dissolve mineral buildup. Don’t forget to thoroughly rinse the detergent tank until water runs clear and leave the cap off to dry completely. Chemical residue hardens during storage and will be difficult to clean later.
Step 2: Protect the engine (gas models only)
According to Hinton, ethanol-laced fuel turns nasty within 30 days, gumming up your carburetor and corroding fuel lines. You’ve got two options: add fuel stabilizer (1 ounce per 2 gallons) and run the engine for 2 minutes to circulate it, or drain everything completely.
Hinton recommends the drain method: “Drain all fuel from the fuel tank and drain or run the carburetor dry for storage.” He also suggests using non-ethanol fuel in all small engine equipment for better performance.
This is also a good time to change your engine oil. Fresh oil prevents acids from attacking internal components during storage. Check your spark plug, too, if it looks fouled or damaged, replace it now rather than dealing with starting issues come spring.
This same preventive approach applies to all your outdoor equipment. Check out: How to Winterize Your Lawn Equipment: A Step-by-Step Guide
Step 3: Drain all water from the system
Leave no water in the system. “Water freezing in a pressure pump can cause the pump housing to crack or break, which will most likely require a pump replacement,” Hinton explains.
This is where sequence matters: turn off the water supply, then shut down the engine, and then squeeze that trigger gun to relieve pressure. Hold all hoses vertically to drain completely. Water loves to hide in spray guns, wands, and high-pressure hoses. These sneaky spots are where freeze damage usually starts.
- Gas models: Pull the recoil starter at least 6 times to force out stubborn water.
- Electric models: Press the trigger while unplugged to release any lingering pressure.
Spray some WD-40 into your pressure washer wand. This does three important things: cleans out any soap left inside, removes mineral buildup, and oils the rubber O-rings. It also helps get rid of any remaining water.
Step 4: Add pump protection
Hinton recommends using pump protection products: “Pressure washers should never be stored over the winter with any water in them. I recommend the use of a ‘Pump Flush’ such as Simpson Universal pressure washer pump guard or something similar. This will force out any water and replace it with a solution that is like antifreeze.”
Commercial pump savers beat regular antifreeze because they include lubricants and corrosion inhibitors specifically designed for pressure washer pumps. If you go the antifreeze route instead, grab the pink RV/marine stuff, not the green automotive antifreeze.
Apply through the garden hose inlet using a short adapter hose. Keep adding until the antifreeze or pump saver exits the pump outlet.
Step 5: Choose the right storage location
Gas models prefer storage above 40 degrees F for optimal engine protection, while electric models are more forgiving of temperature when properly winterized. Keep humidity under 60% if possible, as excessive moisture leads to corrosion that’s expensive to repair. Keep your pressure washer away from heat sources like furnaces or water heaters.
If you don’t have a temperature-controlled space, you can still protect your pressure washer. Put it on a wooden pallet or blocks to keep it off the ground. This stops it from soaking up moisture. Cover it with a waterproof tarp (at least 6-mil thick). Secure with bungee cords but allow airflow underneath to prevent moisture buildup.
In a pinch
If you forgot to winterize and your pressure washer froze, don’t panic. Move it to a warm location and allow it to thaw completely (at least 24 hours). Never attempt to start it while frozen. After thawing, inspect for cracks and leaks, then test with low water pressure before resuming full operation.
FAQs: Your winterization questions answered
With proper antifreeze or pump saver, most units handle temperatures down to 10 degrees F. Below that, consider additional insulation or indoor storage. If not winterized, your pressure washer can be damaged by any freezing temperatures (32 degrees F).
Absolutely, but only if properly winterized with antifreeze or pump saver. Place it on a wooden pallet or styrofoam insulation to prevent cold transfer from concrete floors. Cover with a heavy-duty tarp or moving blanket for extra insulation, and ensure good air circulation to prevent moisture buildup.
You should see pink antifreeze or pump saver coming out of the spray gun, no standing water anywhere in the system, and fuel either drained or treated with stabilizer. Store it in a dry location above freezing temperatures.
Your pressure washer’s winter success
Plan ahead and winterize your pressure washer properly to keep it working for years. The best way to protect your equipment is to prevent freeze damage with simple preparation. Clean your system thoroughly, drain all water completely, add pump protection, and store it properly. This approach stops the most expensive repairs from happening in the first place.
If you prefer to focus on enjoying winter without stressing over equipment maintenance, let Lawn Love connect you with world-class local lawn care professionals who offer leaf removal services, yard cleanups, and lawn treatment programs to get your entire property winter-ready.
Related reading:
- Benefits of Winterizing Your Lawn
- How to Winterize Your Lawn
- Essential Lawn Care Tools for Every Homeowner
- How to Winterize Your Lawn Equipment: A Step-by-Step Guide
Main Image: Store your pressure washer in a temperature-controlled space during winter. Photo Credit: Kirill Gorlov / Adobe Stock
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