How to Winterize a Pressure Washer

If your pressure washer is gas powered, start the winterization process by emptying and stabilizing the gas container. Skip this step if your machine is electric. 

Locate and turn off the fuel shutoff valve. If your machine doesn’t have one, you’ll need to use a siphon to manually empty the fuel into a metal receptacle. Then start the machine and run it for several minutes to use up the remaining gas. 

Next, remove the cap from the gas tank and add two capfuls of fuel stabilizer. Seal it back up and move on to the following step.

While it’s not always necessary to refill your pressure washer’s oil tank before winter (especially if you’ve already done it recently), doing so will ensure it’s ready to use and in great shape by the time warmer weather rolls around. And if your machine is in good working order, you can expect the cost to pressure wash your house to go down, too. 

Find and open the oil drain plug using a socket wrench, then use a metal receptacle to catch the oil as it drains out. It can take upwards of 10 minutes for the oil to drain completely, so be prepared to wait a bit. 

Once drained, seal the oil drain plug and place a gas funnel into the fill-up port. Pour synthetic motor oil into the funnel until the oil tank is completely filled, checking the levels periodically to avoid overspill.

There’s nothing worse than attempting to start up your electric pressure washer come spring only to discover that its battery is somehow drained. Avoid this problem entirely by simply removing or disconnecting the battery before storing it for winter.

Washing up all the bits and bobs of your pressure washer before storing will also prevent it from deteriorating in the winter. Remove the filters and nozzles, and use a toothbrush and straw scrubber or fine needle to get rid of any dirt blockages. Store them separately from your machine, ideally in a closed container where they won’t attract any dust or pests.

Locate the inlet fitting on your machine’s water pump, remove the cap, and attach a two- to three-foot garden hose. Fit the large funnel onto the other end of the garden hose and pour in enough antifreeze to fill it up halfway. 

Locate the water pump outlet fitting, open it, and place a metal or plastic receptacle near the opening to catch the pour-over. Pull the water pump cord to fully circulate the antifreeze and stop when the water leaving the outlet is no longer clear but pink. Seal both inlet and outlet, then remove and dry tools.

Once you’ve taken all these steps, you can safely store your machine in both cold and warm conditions. Just make sure that it won’t be exposed to any moisture to prevent rust from forming.