How to Prepare Your Pressure Washer for Winter

Leaving water-filled equipment outside during winter is probably not the best of ideas.

If you live in northern latitudes where snowfall and freezing temperatures commonly occur during winter, you should already be used to setting up your lawn and equipment for the coldest of the seasons. Regardless of how well you stick to good maintenance practices, in the case of pressure washers, doing so is mandatory. So, how should you go about it?

Don’t be startled! It’s an easy chore which only takes a few minutes and with the right instructions, anybody can do it at home, including you!

Read on to find out how to prepare your pressure washer for winter.

Why Should I Winterize My Pressure Washer?

Let’s face it. Most of us hate chores, especially if we deem them unnecessary. However, this is not the case when it comes to winterizing pressure washers. Hear me out.

Whenever you’re done with using your pressure washer for the day, it’s still pretty wet. While some water drips out from the pressure washer or evaporates quite fast, pockets of sitting water also form inside your washer and stick around for a surprisingly long time, especially in areas such as the pressure washer’s pump.

Molecular structure of liquid and frozen water

Molecular structure of liquid and frozen water

These pockets of water aren’t an issue at reasonable outdoor temperatures. However, that’s not the case during winter! Quite unintuitively, water expands its volume by 9% (opens in a new tab) upon freezing, which may lead to unexpectedly severe damage to any pipes, pumps, seals, etc.

Therefore, unless you store your washer in a heated area, you will need to properly prepare it for the cold!

Winterizing Pressure Washers

Now that you know why, let’s learn how to prepare your pressure washer for winter. In essence, the task is quite simple. All you need to do is get rid of all cleaning liquids in your pressure washer, stabilize or drain the fuel if you have a gas-powered washer, and then, in both cases, store it neatly for the winter.

Before taking any of these steps, consult your user manual to check for the manufacturer’s recommended procedures.

Purge Detergent

First, start off by getting rid of all the detergent left in the detergent tank, if your pressure washer has one. If not, simply skip the first step and follow along the relevant parts using a bucket of warm water and a siphon hose.

Drain the detergent tank and rinse it thoroughly. It may be helpful to detach the tank if your unit allows it. Once the detergent tank is clean, you should fill it up with warm water and run your pressure washer, first at low and then at high setting to purge any remaining detergent from the washer.

Remove All Hoses

Secondly, detach all hoses, lines and other components not only from the body of the washer, but also each other. This will help all components to dry properly and prevent them from getting stuck together over time.

Make sure to squeeze the washer’s gun repeatedly, until no water is ejected by doing so. Then proceed to take everything apart. Generally, the right order is to disassemble from the bottom up, starting from the inlet hose and ending with the pressure washer tip, to allow the water in the washer to drain neatly from the top down.

However, to drain the washer more efficiently, it may be helpful to start with the washer’s gun, since its narrow end blocks air and may create a vacuum-seal effect. After that, proceed from the bottom as described.

Purge Water

Next, you will need to purge all remaining water from the body of the washer. It may be helpful to use a compressor to help you along with the task, though it is not mandatory and certainly should be avoided if it is not recommended by your unit’s manufacturer.

After completing the previous steps, start up your pressure washer at a low setting (for electric units) or gently pull the started cord a few times (for gas units), and wait for the initial stream of water to stop spraying. Then, rock around your unit from side to side until no additional water is ejected upon doing so. If you have a compressor, attach it to the water inlet and let it run for a couple of seconds at a low setting during this process.

Avoid running your washer without water for more than a couple of seconds, as this will likely damage its pump, which is designed to act against a body of water.

Use a Pump Saver

In addition to all the aforementioned steps, it is also often recommended to use a so-called pump saver. A pump saver is an antifreeze-like liquid intended to protect your pump directly from damage related to or caused by its freezing. Given that unlike a replacement pump, pump savers only cost a few bucks, you may as well use them while you’re at it. Consult your user manual for the preferred pump saver.

Pump savers are sold in either pressurized or unpressurized containers. The container type will be specified on the container. Pressurized containers can also be easily distinguished by their design, as they usually have threading on their head and a button on the top of the container.

Apply pump saver only AFTER you have purged all water from the pressure washer. Start by fitting the container on your water inlet. Most containers will have matching threading, though some unpressurized containers might not. In both cases, the container must fit well with the water inlet and should NOT be used if that is not the case.

After you have successfully fitted the container onto the inlet:

  • For pressurized containers: Simply push the button on the top of the container…
  • For unpressurized containers: Gently pull the starter cord 5 to 6 times to pull the solution through the pump…

And continue doing so until you see liquid pouring out from the washer’s outlet.

What Should I Do With Leftover Fuel? (Gas Only)

If you own a gas-powered washer, you still have some liquid to worry about – fuel. Under normal circumstances, gasoline doesn’t freeze easily and at low temperatures actually contracts in volume. However, if it is left sitting around for long periods of time, fuel can form gunky deposits (opens in a new tab). Therefore, leaving gasoline in the gas tank over winter is possible ONLY IF you use a fuel stabilizer.

Alternatively, you may simply drain any unused fuel from the tank. It is often recommended to follow that up with running the washer to burn any leftover fuel (opens in a new tab). However, we discourage you from doing so unless it is explicitly specified in the device’s user manual. If you chose to run your washer anyways, do it BEFORE you apply pump saver!

Storing a Pressure Washer Over Winter

Lastly, make sure to store your pressure washer in suitable conditions over winter. Your user manual will have more specific recommendations on how to do so. However, in general, power tools and outdoor equipment should be stored in (preferably) reasonably insulated sheds or garages, or any equivalently suitable cool and dry space (opens in a new tab). Power equipment should NEVER be stored outside!

If you own a gas-powered pressure washer, it is recommended to disassemble and store the spark plug away from the spark plug wire.


In summary, we have covered why and how a pressure washer should be stored over winter. To recap, purge detergent, disassemble all hoses and lines, and then purge all remaining water from your washer. Use a pump saver to protect the washer’s pump more thoroughly. Either stabilize your fuel by adding fuel stabilizer to it or drain all fuel. Finally, make sure to store your pressure washer over winter in a suitable place.



Manager & Editor of Mechanical Engineer by trade, he specializes in power tool design and works for a global player in the OPE industry.

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