Graham FisherBy Graham Fisher

Updated November 2026

Learning how to winterize a pressure washer takes about 20 to 30 minutes and protects the pump, hoses and seals from freezing. The core job is to remove all water from the machine and replace it with non-toxic pump antifreeze. Once that’s done, the unit can sit in a cold garage or shed without cracking anything.

Why Winterizing Matters

Water expands by roughly 9 percent when it freezes. That expansion can crack pump heads, split hoses and damage the unloader valve. Even a small amount of trapped water in the pump is enough to cause trouble. Manufacturers consistently advise draining and protecting the machine before temperatures drop below freezing.

Shopping for one? See our guide: 7 Best Green Work Pressure Washers for Home Use (2026).

Step-by-Step: Draining and Protecting the Pump

  1. Turn off the engine or motor and disconnect the water supply.
  2. Squeeze the trigger on the spray gun to release remaining pressure, then engage the safety lock.
  3. Remove the spray wand and nozzle, and drain any water from the hose by coiling it and letting it sit at a low point.
  4. Place the inlet hose into a container of pump antifreeze, or attach a dedicated winterizing adapter if your model has one.
  5. Run the engine or motor for 30 to 60 seconds with the trigger pulled, until pink or blue antifreeze comes out of the spray gun end. Release the trigger and shut the unit off.

Handling the Engine and Fuel

On gas models, stale fuel gums up carburetors over winter. You can either run the engine dry or add a fuel stabilizer to a full tank and run it for a few minutes so the treated fuel reaches the carburetor. Owners often report fewer no-start problems in spring when they do this step.

Task Gas Models Electric Models
Drain water from pump Yes Yes
Add pump antifreeze Yes Yes
Stabilize or drain fuel Yes Not applicable
Store upright in dry space Yes Yes

Storing the Machine Through Winter

Store the unit in a space that stays above freezing if possible, and keep it upright so oil and fluids don’t leak. Cover it to keep dust out, but avoid sealed plastic bags that trap moisture. Before first use in spring, check the oil, inspect hoses for cracks and flush the antifreeze out with clean water. If you have questions about your fuel or engine, the Gas for Pressure Washer: What Fuel to Use and How to Avoid Damage guide covers fuel choices in more detail. Owners who rent equipment should also review Pressure Washer Machine Rental: How to Choose, Prep and Save Time before returning or storing rented gear.

Common Mistakes

  • Skipping the antifreeze step and assuming draining is enough. Residual water can still freeze in the pump.
  • Using automotive antifreeze, which can damage seals. Use pump-specific, non-toxic antifreeze.
  • Storing the unit in a freezing garage with the hose still attached and full of water.
  • Running the engine without antifreeze in the pump, which can cause dry running damage.
  • Forgetting to check for leaks and cracked hoses before spring startup.

Pump antifreeze made for pressure washers is the single most useful supply for this job, since it protects seals and internal parts without leaving residue. A winterizing adapter or inlet hose lets you draw antifreeze directly from a jug without pouring it into an open container. View on Amazon

A fuel stabilizer helps gas models keep fuel fresh through storage periods. View on Amazon

FAQ

Can I use RV antifreeze to winterize a pressure washer?

Many owners use non-toxic RV antifreeze, but manufacturers generally recommend pump-specific antifreeze. Check your owner’s manual before using any product, since some formulas may not suit the seals in your model.

Do electric pressure washers need winterizing too?

Yes. Electric models still have water in the pump and hose that can freeze and crack components. The draining and antifreeze steps apply the same way.

How do I know if my pressure washer froze?

Look for cracked pump housings, leaks around the pump, or a unit that won’t build pressure after warming up. If you spot damage, consult a qualified repair technician before running the machine.

Conclusion

To winterize a pressure washer, drain the water, run pump antifreeze through the system and stabilize any fuel in gas models. Store the unit upright in a space that stays above freezing. Taking these steps each fall prevents costly cracks and makes spring startup far easier.

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Graham Fisher

About Graham Fisher

Graham Fisher is part of our editorial team and reviews and edits our non-vacuum cleaning gear guides, checking product details against manufacturer specifications and owner feedback.