How to Winterize a Pressure Washer

Updated 3/8/2023

After a summer full of power washing projects, once you begin to feel the chill in the air (or rather, in the case of my home state of Illinois, “once you begin to feel the sub-zero degree blasts of death by September that signify subarctic conditions likely to linger until the following May”), it’s time to safeguard and winterize your pressure washer.

Knowing how to winterize a pressure washer is one of the most important things you can do to ensure your machine’s durability and efficiency.

It would be best to winterize it when you plan to store your pressure washer for 30 or more days. However, it is particularly essential over the winter. 

Not properly preparing your pressure washer for winter could result in a broken pump and damage to other components.

Many pressure washer owners dislike having to do this, and many completely ignore it.

However, this process will only take a few minutes, and your pressure washer will be ready to be stored and prepped to get back to cleaning when the time comes.  

Why Should You Winterize Your Pressure Washer?

Even if you are storing your pressure washer in a garage, shed, or basement and don’t plan to use it for several weeks, you should still winterize it.

Garages and sheds aren’t insulated enough to protect the washer against freezing temperatures. A prolonged period of inactivity can also damage the machine.

Long storage times and cold temperatures can lead to cracks in the pump system. Water left in the machine can freeze, expand, and damage the pressure washer’s hoses.

It can also grow mold and mildew, which eats away at the seals and clogs the lines.

This can result in a leaky pressure washer that can end up in the garbage bin.

Unfortunately, warranties won’t cover pressure washers damaged due to lack of maintenance. It’s like throwing money away; for many pressure washers, that’s several hundred dollars.

How to Winterize a Pressure Washer

It is important to winterize both gas pressure washers and electric pressure washers. Each method differs slightly from the other, with gas being a little more time-consuming.

In this section, you will learn how to winterize a pressure washer in a few simple steps that can be completed quickly.

Each time your machine is stored for more than 30 days, these steps must be taken.

1) Stabilize the Gasoline

The first step is to add a fuel stabilizer to the fuel tank when purchased. This will make sure the gas doesn’t clog the fuel lines during storage.

Adding a fuel stabilizer to fuel sitting in the pressure washer for over 30 days will not preserve the gasoline.

The stabilizer only preserves the condition the fuel is in when applied.

Moreover, deteriorated fuel causes a higher chance of your pressure washer’s fuel tank breaking down. This can result in rust, corrosion, and build-up.

Using a fuel stabilizer can combat the effects of this deterioration and breakdown. You should add it according to the manufacturer’s directions, run the engine for 2 minutes to circulate the stabilizer throughout the fuel system, and then shut it down.

If you plan on storing your unit in your basement, make sure to drain the gasoline from the unit before storage.

Always store your pressure washer in a clean, dry, well-ventilated area, away from open flame or sparks.

2) Flush Out Remaining Water

All water and leftover detergent should be flushed from the system. You should place the injection tube of your power washer into a bucket of clean water and run the unit in a low-pressure setting for a minute or two to clean out any sediment or debris.

You should then turn off the engine and water supply, squeeze the spray gun trigger to relieve the pressure, and set the lock.

Once that has been done, you should also disconnect and dry all attachments and put them away properly.

Though the pump may still have leftover water, it can be taken care of by pulling the recoil handle a few times.

3) Add a Pump Saver

Lastly, extend the life of your pump by adding a Pump Saver. You should apply it through the garden hose inlet on your pump to fill the chamber, allow it to stay there all winter, and drain it in the spring. 

A pump saver stops moisture from forming in the pump, keeps the internal parts of your pressure washer pump lubricated, and prevents it from freezing.

It also allows for easy starting post-storage and prevents mineral deposits from developing.

You should follow the instructions on the bottle of pump saver and leave the liquid in the pump all winter.

Upon start-up in the spring, the pump saver will naturally flush out of your pump.

4) Don’t Forget the Cover!

Storage covers help protect pressure washers from dust, bugs, spider webs, moisture, mice, and rust.

Covers made of cloth (often polyester or canvas) with a water-resistant coating like polyethylene allow the pressure washer to breathe while protecting it from moisture damage.

Remember that the storage cover should be water-repelling, water-resistant, or waterproof. 

If you must keep your pressure washer outside for any reason, you will need a cover to protect it from the sun and precipitation. The more waterproof the cover is, the better.

Many covers fit all sizes of pressure washers. Still, to be safe, you should take accurate measurements of your pressure washer and get a cover according to those specific measurements to ensure the perfect fit without exposing any parts of the washer.

If you find yourself in a pinch, a tarp or BBQ grill cover can work with a few adjustments.

Final Words

Part of owning a pressure washer is understanding how to store it properly in the off-season. For many of us, it usually means the winter months.

For others, in more temperate climates, that can mean an extended period of several weeks when you know you won’t be using it.

As my dad always said, “take care of your gear, and your gear will take care of you.”

Therefore, you need to know how to winterize your pressure washer properly so that you can use it in a stress-free way next time.

Hopefully, this guide answered the question of how to winterize a pressure washer!

Until next time, readers! 

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