How to Winterize a Pressure Washer: Step-by-Step Guide
Quick answer: Winterize before the first freeze: stabilise the fuel on a gas unit, run pump saver antifreeze through the pump, drain the hose, gun and wand, and store the machine somewhere dry. Freeze and thaw can crack the pump, seals and hoses.
Last updated: October 2026. Water left in a pressure washer can freeze, expand and crack the pump. This guide combines steps from All Parts Inc., Pumptec and Greenworks. Always check your own manual, since methods vary by model, and if in doubt ask a dealer for advice on your particular machine.
Why should you winterize?
Pumptec says freeze and thaw expansion can damage plumbing, seals and hoses, and can cause pump failure. Greenworks recommends winterizing whenever you store a machine for more than 30 days. A repair or replacement pump can cost a large part of the price of a new machine, so a few minutes of prevention pays off.
How do you winterize a gas pressure washer?
All Parts Inc. lists seven steps.
- Add fuel stabiliser, then run the engine for 5 minutes with a garden hose connected and the high-pressure hose removed.
- Add pump guard, a non-toxic antifreeze made for pressure washers.
- With the engine off, slowly pull the starter rope several times to cycle the pump saver through the pump.
- Disconnect the spark plug wire.
- Drain the hose, gun and wand by squeezing the trigger.
- Lubricate external parts with WD-40 or silicone spray.
- Store in a clean, dry place away from heat.
How do you winterize an electric pressure washer?
Greenworks says to disconnect all hoses and drain the machine, run it briefly with no hose attached, then use pump saver or RV-type antifreeze. Connect the bottle to the inlet and squeeze until product exits the outlet. Electric machines do not need fuel stabiliser. Store the unit indoors on a shelf or wood, not directly on concrete.
What extra steps does Pumptec add?
- Blow out the gun, wand and hose with compressed air.
- Rinse with a small amount of antifreeze.
- Clean the pump filter and nozzles.
- Store somewhere dry and ideally non-freezing.
What supplies do you need?
| Item | Use |
|---|---|
| Pump saver or RV antifreeze | Protects the pump |
| Fuel stabiliser (gas) | Prevents stale fuel |
| Compressed air (optional) | Clears water |
| Silicone spray | Protects fittings |
| Clean rags | Wipe down |
When should you winterize?
All Parts Inc. says to winterize before the first freeze and gives no temperature threshold. Do it at the end of the season, not after a cold snap.
How do you restart in spring?
- Reconnect hoses and check O-rings.
- Connect water and squeeze the trigger until air is purged.
- Check oil and fuel on gas units.
- Start the machine following our starting guide.
- Look for leaks before working at pressure.
What mistakes ruin pumps?
Skipping antifreeze, leaving water in the hose and storing the machine in an unheated shed are the most common. Never run a pump dry. See our hose guide for care of hoses, and remember to drain accessories such as foam cannons and surface cleaners too.
What about oil and fuel?
Check our oil guide for pump and engine oil. Use fresh fuel with stabiliser on gas machines, and store the container away from heat. Consider changing engine oil at the end of the season so old oil does not sit in the crankcase all winter.
How long does winterizing take?
Most owners can finish in 15 to 30 minutes once the supplies are on hand. A gas machine takes a little longer because of fuel stabiliser and the engine run. Set a reminder in your calendar for the end of the season so it does not slip.
Winterizing checklist by machine type
| Step | Gas | Electric |
|---|---|---|
| Fuel stabiliser | Yes | No |
| Pump saver antifreeze | Yes | Yes |
| Disconnect spark plug wire | Yes | No |
| Drain hose, gun, wand | Yes | Yes |
| Store dry, off bare concrete | Yes | Yes |
What if you forgot and the water froze?
Do not start the machine. Let it thaw indoors, then inspect the pump, hoses and fittings for cracks or leaks before you connect water. If you see water leaking from the pump when you run it, stop and get it checked. Repair may cost more than the machine is worth, which is why prevention matters.
Frequently asked questions
When should I winterize my pressure washer?
Before the first freeze, or whenever you store it for more than 30 days according to Greenworks.
What antifreeze should I use?
Pump saver or RV-type antifreeze, per Greenworks.
Do electric washers need fuel stabiliser?
No.
Can I store it in a cold garage?
Only if you have drained it and used pump saver. Indoor storage is safer.
Final verdict
Drain, protect the pump with antifreeze and store dry. It takes about 15 minutes and can save a costly pump.
Sources: All Parts Inc., how to winterize a pressure washer; Pumptec, winterizing guide; Greenworks, electric pressure washer winterizing. Related: How to start a pressure washer, What oil to use, Pressure washer safety.
