Operating Your Cold Water Pressure Washer Out of Season: It Can Be Done!

Despite the cold weather there are still times when you want to take on a pressure washing job to clean a surface of your property. Dressing up your home or office by pressure washing sidewalks, front porches, driveways, or cleaning pressure-treated wood decks, can be a quick way to brighten your entranceway for the arrival of family and friends.

Successfully completing your “off season” pressure washing tasks can be done if you simply heed a few instructions and precautions in preparing and operating your equipment, and most importantly, by winterizing your pressure washer after the job is completed. By following the steps outlined below, carefully, you can accomplish your cleaning goals and at the same time, protect your valuable piece of equipment for trouble-free use later in the year.

Follow these guidelines when using a cold water pressure washer:

  • Keep the unit on a level surface
  • Check engine oil for proper level – fill with 10W30 motor oil to proper level


  • Check the oil in the water pump by unscrewing the dip stick, usually located in the top of the water pump – fill with 30 weight, non-detergent, oil to the proper level (do not overfill)


  • BEFORE STARTING – make sure all hose and spray tip quick-connect fittings (if s0 equipped) are in the locked position. Select the proper tip for your job
  • Use a garden hose measuring at least ¾” ID (inside diameter) and no longer that 50 feet in length
  • Check to make sure you have an adequate water supply. Incoming Gallons per Minute (GPM) must be at least one gallon or more, higher than what is stated on the pressure washer specification plate, located on the machine. You can check your home’s GPM flow by timing how long it takes to fill a 5 gallon container.
  • Turn on water supply and hold the trigger of gun before starting – this purges the air out of the system and allows water to pass through the pump while turning.
  • Once the air is purged from the system trigger the gun and start the unit.  Check for water, oil and fuel leaks. If any leaks are found turn the unit off immediately
  • IMPORTANT – do not operate the unit in bypass mode (with gun not triggered) for more than two minutes without triggering the gun. Failure to follow this simple rule can cause premature failure of pump seals and plungers resulting in a costly pump repair.


  • Turn engine switch off
  • Turn off the fuel valve between the fuel tank and engine (very important!)
  • Trigger the gun to relieve back pressure
  • Once water pressure is relieved , disconnect the hose, gun and nozzle
  • Drain water from the hose and gun before storing them


For storage and transportation purposes in subfreezing ambient temperatures it is ABSOLUTELY necessary to winterize your pressure washer. 

  • Change pump and engine oils at least once a season
  • Antifreeze should be kept in water pump for winter storage
  • Add fuel stabilizer to gas tank for the winter, making spring start-up a little easier


Finally, in cold weather, make sure you disconnect the garden hose from the hose bib and remember to turn off the water supply to the hose bib. Leave the hose bib valve open to ensure that all water has drained from the hose bib to ensure that no ice can build up internally that could damage your water pipes.

If you don’t own a cold water pressure washer, McCormick Paints offers full-day rentals on pressure washing equipment at every one of our mid-Atlantic store locations. Not sure how to operate one? Don’t worry! Our expert staff will be happy to show you how to successfully operate a pressure washer to help you complete your “off season” pressure washing job.