How to winterize a pressure washer

Winterize a pressure washer before temperatures can drop below freezing. Drain all water from the pump, hose, spray gun, and accessories, then protect the pump with a manufacturer-approved pump protector or antifreeze product. Gas models also need fuel preparation, while electric models need careful drying and protected storage.

What you need

Gather the items recommended in your owner's manual. Depending on the pressure washer, you may need:

• Pump protector or pressure washer pump antifreeze
• Fuel stabilizer for a gas-powered model
• A clean, dry cloth
• A suitable storage cover
• Wrenches or pliers only if the manual calls for removing fittings

Do not use automotive antifreeze unless the manufacturer specifically approves it. Some automotive products contain additives that may damage pump components or create a disposal concern.

How to winterize a pressure washer

1. Turn off and disconnect the pressure washer

For an electric pressure washer, switch it off and unplug it. For a gas model, shut off the engine and let it cool completely before maintenance.

Disconnect the water supply. Relieve pressure by squeezing the spray-gun trigger while pointing the gun in a safe direction. Never service a running pressure washer.

2. Drain the water supply and hose

Remove the garden hose from the inlet and drain it fully. Disconnect the high-pressure hose from the pressure washer and spray gun, then hold or coil it so trapped water can run out.

Inspect the hose for cuts, crushed sections, damaged fittings, or cracked O-rings. Store it loosely coiled rather than sharply bent.

3. Drain the pump

With the machine turned off and the water disconnected, tilt the pressure washer only as allowed by the owner's manual so remaining water can drain from the pump. Some models specify a particular orientation; follow that instruction rather than turning the unit on without water.

Do not run most pressure washers dry. A pump can be damaged quickly without a water supply for cooling and lubrication.

4. Add pump protector

Pump protector is the most important step for storage in freezing conditions. Connect the product to the pump inlet or the fitting specified by the manufacturer. Press the product's button or valve until the protectant exits through the pump outlet, or follow the product instructions for the required amount.

This pushes residual water out and leaves a protective fluid inside the pump. Reconnect caps or fittings afterward to keep dirt and insects out.

If the manual specifies a particular pressure washer antifreeze, pump saver, or storage procedure, use that method. Different pump designs may have different requirements.

5. Prepare a gas pressure washer's fuel system

For a gas-powered pressure washer, check the engine manual before choosing between draining the tank, adding fuel stabilizer, or both. Common options include:

• Add the specified amount of fuel stabilizer to fresh fuel, then run the engine long enough to circulate the treated fuel through the system.
• Drain the fuel tank and carburetor if the manufacturer recommends empty storage.

Never add fuel or stabilizer while the engine is hot. Work outdoors or in a well-ventilated area, keep fuel away from flames and ignition sources, and store gasoline only in an approved container.

Change the engine oil if the maintenance schedule calls for it before storage. Protect the air filter, spark plug, and other engine components according to the manual.

6. Dry and protect an electric pressure washer

Wipe moisture from the frame, motor housing, electrical connections, and controls. Keep the plug and extension cord dry. Do not wrap a wet cord tightly around the machine.

Store the unit in a dry location protected from freezing temperatures. A cover can reduce dust, but do not cover the machine while it is wet or warm, and do not block ventilation openings.

7. Store the hose, gun, wand, and nozzles

Drain and dry every accessory. Remove spray tips from the wand and clean dirt from the nozzle openings. Store nozzles where they will not be crushed or lost, and protect metal fittings from prolonged moisture.

Do not leave detergent in a tank, siphon tube, or onboard detergent system. Rinse the detergent path with clean water if the manual permits it, then drain it.

Where to store a pressure washer

Store the pressure washer upright in a dry, sheltered area that will not freeze. Keep it away from direct heat, pilot lights, corrosive chemicals, and areas where gasoline vapors could collect.

Do not rely on a garage heater to prevent freezing unless the space is consistently maintained at a safe temperature. A short cold snap can still leave water trapped in the pump or hose.

What to do before using it again

When the weather warms up:

1. Inspect the power cord, fuel line, hoses, fittings, O-rings, and spray wand.
2. Confirm that the pump protector has been cleared according to the product instructions.
3. Install the correct filter, nozzle, and hose connections.
4. Connect the water supply and turn on the water before starting the machine.
5. Squeeze the spray-gun trigger until air is purged and water flows steadily.
6. Check for leaks before applying engine power or plugging in an electric model.

Use fresh fuel and the correct engine oil if required. If the motor runs poorly, the pump leaks, or the pressure washer will not build pressure after proper setup, stop using it and consult the manual or a qualified repair professional.

Common winterization mistakes

• Leaving water in the pump: Freezing water can expand and crack pump components.
• Running the machine without water: This can overheat or damage the pump.
• Using the wrong antifreeze: Use only a product approved for the pressure washer or pump.
• Storing a gas model with untreated fuel: Fuel can degrade and cause carburetor or starting problems.
• Covering a wet machine: Trapped moisture encourages corrosion and electrical problems.
• Forgetting detergent lines: Residue can clog the siphon tube or detergent valve.

If the pump has already frozen and the housing is cracked, winterization will not repair it. Replace the damaged part or have the unit inspected before operating it again.