man wearing winter safety equipment pressure washing in the snow

How to Winterize Your Pressure Washer: A Step-by-Step Guide

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As the temperatures drop and winter approaches, it’s time to think about protecting your pressure washer. Whether you own a gas or electric model, hot-water or cold water, winterizing your pressure washer is essential to prevent damage from freezing water and ensure it’s ready to go when you need it.

Winterizing Basics

Winterizing is simply the process of removing water from the pressure washer, along with other measures to ensure safe storage. The “best way” may differ depending on your situation. If you use your machine throughout the winter, quick and simple will be your best choice. If you put things away for a season you may want to add a few steps to ensure readiness when you go to use it again. Either way, a few simple steps can save you hundreds of dollars and extend the life of your machine.

Step-by-Step Winterizing Process

1. Flush Out Detergents

If you use soap or detergent, run clean water through the system to flush out any residue. Leftover chemicals can corrode internal parts over time.

2. Drain All Water

Disconnect the garden hose, spray gun, and high-pressure hose from the pressure washer, and separate them. Water can be removed from these components by simply draining them. Hold the gun tip up vertical, pull the trigger and let any water flow out of its inlet. Remove and drain larger nozzles (such as a turbo nozzle) and store all nozzles in their holders or any dry place. For the hoses, lay them out straight on a flat or sloped surface and hold one end up to let the water flow out the other end. You can then walk the “high spot” down the length of the hose to ensure it’s empty.

For the machine, it depends on the type you have:

  • Cold Water Pressure Washers: Run the pump briefly and let it spit out the water inside the pump; with gas engine units this should be done without starting by pulling the starter rope multiple times. For an electric unit, a quick on and off cycle of the switch will work. *Note – this process only takes a few seconds, running your pump dry for longer than 5-10 seconds may cause internal damage.
  • Hot Water Pressure Washers: Hot water units will always hold water in the heating coil. These cannot simply be drained, the water must be displaced by either circulating anti-freeze solution using the pump, or by blowing out with compressed air.

3. Purge with Antifreeze or Compressed Air

Choosing which method is best will depend on how long you plan on storing your pressure washer. For short-term, draining a cold-water unit as described or blowing the water out with compressed air will be sufficient to prevent damage from freezing. Start by reducing the pressure output on your compressor to under 30-50 PSI and use multiple short bursts of air (1-2

seconds each). You will observe that by letting it rest and applying air again, you will expel even more water. If you plan on storing your machine for longer, filling the components with RV anti-freeze will be better. RV anti- freeze keeps internal parts like seals and O-rings lubricated, preventing them from drying out, shrinking, or cracking during storage.

You can purchase a “Pump Saver” product to help get the anti-freeze solution into the pump of your cold-water machine, or simply connect a scrap end from an old garden hose (not more than 2-3 feet long) to your pressure washer’s inlet and put the cut end into the anti-freeze jug, then pull over the starter or briefly run the unit to pull the anti-freeze in until it comes out of the discharge fitting. For hot water units, you will need enough anti-freeze to fill the entire heating coil, probably just 1 or 2 gallons, but that will depend on its size. Done!

4. Prepare the Engine (Gas Models Only)

If you will be storing your pressure washer, or any gas-engine equipment longer than 2 months, follow these additional tips to ensure easy startup next season.

The best practice for short term storage (1-3-months) is to ensure that gasoline is not left in the carburetor or fuel system. To do this you can simply shut off the fuel valve (if equipped) and run the engine until it dies. Do this prior to winterizing the pump, since you need water connected to the pump’s inlet to run for this amount of time. If your engine does not have a fuel shut off, then drain the gas tank and run the engine to burn off any fuel left in the system.

For longer-term storage(over 3-months) draining the gas or using a fuel stabilizer will help the gas from going bad in your tank. Do not add fuel stabilizer directly to the gas in your tank. Fuel stabilizers should be mixed with fresh gas when filling your fuel can. If the gas in your engine’s tank does not have stabilizer already mixed in, draining the fuel is best.

It also helps to remove the spark plug, pour about a teaspoon of engine oil into the cylinder and pull the starter over slowly multiple times to lubricate the piston and cylinder wall. For electric-start machines, disconnecting the negative battery cable when finished can prevent battery drain while in storage.

5. Store Properly

  • Keep the pressure washer in a dry, sheltered location like a garage or shed.
  • Avoid storing it outside or in unheated areas where temperatures drop below freezing.

When to Winterize Your Pressure Washer

Knowing the right time to winterize your pressure washer comes down to temperature, not the calendar. The critical point is when temperatures are expected to fall near or below 32°F (0°C), even overnight.

  • Consistent Freezing Temps: If your area is seeing regular nighttime freezes, it’s time to winterize.

  • Unheated Storage Spaces: Even if daytime temps stay mild, pressure washers stored in garages, sheds, or other unheated spaces can freeze overnight.

  • Occasional Use in Winter: If you still plan to use your machine during cold weather, take extra precautions. Drain it after every use and use compressed air or antifreeze between jobs to prevent ice damage.

  • Warm-Climate Owners: In regions where it rarely drops below freezing, you may not need full winterization. However, draining water after use is still smart to prevent mineral buildup and keep seals in good condition.

The bottom line: as soon as temperatures approach freezing in your storage area, winterize. A single hard freeze can crack pumps, coils, or hoses and cause expensive repairs.

Spring Start-Up Checklist

When winter ends:

  • Flush antifreeze by running clean water through the system.
  • Refill the fuel tank with fresh gasoline.
  • Reconnect the battery and check spark plug condition.
  • Test spray patterns to confirm consistent pressure.

This ensures your washer starts the season smoothly.

Protect Your Investment Year-Round

Winterizing is more than a seasonal chore; it’s an investment in the longevity of your pressure washer. By draining water, treating the fuel system, and storing the unit correctly, you’ll prevent expensive repairs and extend the lifespan of your equipment.

With over 20 years of experience outfitting contractors, municipalities, and homeowners with reliable pumping equipment, Seattle Pump has seen firsthand how preventive care protects performance season after season. Our technicians not only service pumps in the field but also train customers on best practices, giving you confidence that the advice here is tested and proven.

Seattle Pump offers expert service, pump saver fluids, and replacement parts to help you maintain your pressure washer with confidence. Contact our team to learn more about proper storage, routine maintenance, and seasonal service packages tailored to keep your machine running at its best.