How to Store a Pressure Washer

Written & researched by Elena Marsh Gardening & Landscaping Editor

Updated October 2026

Between uses: flush the detergent out, disconnect the water, squeeze the trigger to release the pressure, drain the hose and gun, and store the machine indoors. For winter, add one more step that matters more than all the others — push pump antifreeze through the inlet to displace the water left inside the pump. Water expands about 9% when it freezes, and the residual water trapped in a pump is enough to crack the housing. That is the single commonest way a pressure washer dies, it happens over one cold night, and it is excluded from essentially every warranty on the market.

We never buy, test or physically handle the products we mention; recommendations come from aggregated owner reviews and published guidance, described in how we rank. More at the leaf blowers and yard cleanup hub.

Between uses: the five-minute routine

Do this every time and the machine will outlive its warranty by years.

1. Flush the detergent out. With the soap tank empty, fit the black low-pressure nozzle and run clean water through the siphon for a minute. Detergent left in the injector dries and blocks it, and that is why the soap stops drawing next spring.
2. Run clean water through the pump for two minutes with a wide nozzle. This clears grit that would otherwise sit under a valve seat.
3. Shut down, then bleed. Kill the engine or unplug the machine, turn off the water supply, disconnect the garden hose, and squeeze the trigger until the stream stops. A charged hose stores enough energy to injure you hours later.
4. Drain the hose, gun and wand. Hold the hose up at one end and walk it out. Water sitting in a coiled hose is what freezes first.
5. Pull and rinse the inlet filter screen. It is the small mesh screen behind the garden hose connection, it clogs with sediment, and almost nobody knows it exists. A blocked screen is the leading cause of surging and pulsing.
6. Store it indoors, upright, with the hose coiled loosely rather than kinked around the handle.

Why freezing kills a pump

An axial or triplex pump holds water in passages you cannot reach — behind the valve seats, in the unloader bypass loop, in the manifold. Tipping the machine and letting it dribble does not empty them. When that water freezes it expands, and because the passages are rigid the expansion has to go somewhere: it splits an aluminum manifold, cracks a plastic housing, or blows a seal off its seat.

The symptom in spring is distinctive. The engine or motor runs perfectly, the machine sounds normal, and there is either no pressure at all or a weak stream that never builds. Because the crack is internal there is often no visible leak until you run it. And because manufacturers know exactly how common this is, freeze damage is written out of the warranty on effectively every machine sold in the United States — you will find the exclusion in the manual of the one you own.

Winterizing, step by step

Budget twenty minutes. Do it on a day above freezing, outdoors, with the machine on a level surface.

1. Run the detergent system clear with clean water, as above. Two minutes.
2. Flush the pump with clean water for two more minutes, using a 25° or 40° nozzle.
3. Shut down and disconnect. Engine off or unplugged, water off, garden hose off, then squeeze the trigger to bleed every last bit of pressure. Do not skip this — you are about to open the inlet.
4. Drain everything. Tip the machine to empty the pump, drain the high-pressure hose, drain the gun and wand, and empty the detergent tanks so they do not freeze and split.
5. Add pump saver. Screw the can onto the pump's water inlet and press until you see the antifreeze come out of the outlet fitting or the wand connection. That confirms it has pushed the residual water out of the passages rather than just filled the inlet.
6. Deal with the fuel if it is a gas machine — see the next section.
7. Change the pump oil if the pump has a fill plug and it is due. Most homeowners never do this once, and it is a five-minute job at the interval in the manual.
8. Store above freezing if you can, off the concrete floor, with the hose coiled loosely and the nozzles in a bag so they do not vanish.

Two pump savers dominate the US market and both are widely owned:

• STA-BIL Pump Protector (paid link) — the most-owned product in the category by a wide margin, an aerosol that screws onto the inlet and pushes through in seconds.
• Briggs & Stratton Pump Saver (paid link) — the same job, and the version many manufacturers reference in their own manuals.

RV antifreeze is the field alternative, and it works: the propylene glycol type sold for potable water systems is non-toxic and will not harm seals. Pour it into the inlet with a short length of hose and pull the recoil starter a few times with the ignition off — that turns the pump and draws it through. It is messier and slower than a can of pump saver, and it does not lubricate the seals the same way, but it beats doing nothing. Never use automotive ethylene glycol antifreeze: it is toxic, and it will end up in your driveway and your garden in spring.

Gas machines: the fuel is the other half of the job

Stale fuel causes more spring no-starts than every mechanical fault combined. Ethanol-blended pump gasoline begins degrading within about 30 days and is hygroscopic — it pulls in atmospheric moisture, which separates out as a water layer at the bottom of the tank and leaves gum and varnish in the carburetor's jets. There are two acceptable approaches and one unacceptable one.

If you stabilize, fill the tank nearly full rather than leaving it part empty — the air space above the fuel is where condensation forms. STA-BIL Storage fuel stabilizer (paid link) is the standard product and treats far more fuel than a pressure washer tank holds, so one bottle covers the mower and the blower too.

Also change the engine oil before storage rather than after. Used oil carries combustion acids that sit against bearing surfaces all winter, and warm oil drains far more completely than cold oil does — so do it at the end of the last job, not on a cold morning in April.

On storing the fuel itself: FEMA's basement and garage fire safety guidance recommends keeping gasoline in a shed away from the house rather than in an attached garage, and never near an appliance with a pilot light or a water heater. Use an approved container, not a jug.

Electric machines: what is different

No fuel, no oil, and a shorter list — but the pump still freezes and cracks exactly the same way, so the flush-drain-pump-saver sequence is identical. Three additional points.

• Coil the cord loosely, in wide loops rather than tight wraps around a hook. Cold makes cable jackets stiff, and repeated tight coiling in the cold is what breaks conductors near the plug.
• Check the GFCI plug before you put the machine away and again before first use in spring. Press test, press reset. The CPSC has issued a run of recalls on machines shipped without a working ground-fault plug, so this is not a formality.
• Do not store it on a damp concrete floor. Concrete wicks moisture, and corrosion in the motor housing and the switch is a real failure mode. A shelf or a pallet is enough.

Bringing it out in spring

1. Look before you start. Check for rodent nests in the engine shroud, chewed fuel lines and wiring, and cracked hose.
2. Fresh fuel in a gas machine, always — even stabilized fuel from last autumn is worth replacing if it has been more than a year.
3. Connect water first and purge. With the machine off and the water on, squeeze the trigger and run water through for 30 to 60 seconds until the stream is steady and free of spitting. This flushes out the pump saver and removes air. Never start a pump dry.
4. Check the oil level in both engine and pump before the first pull.
5. Expect the first minute to look odd. Pump saver colors the water for the first few seconds. That is normal.
6. If it runs but makes no pressure, the pump was probably frozen. Work through the surging and pressure-loss checklist before assuming the worst — a blocked inlet screen produces similar symptoms and costs nothing to fix.

Safety

Two things to be deliberate about. Bleed the pressure before opening anything. Shut the machine down, turn off the water, and hold the trigger until flow stops. A high-pressure stream can penetrate skin and inject water and debris underneath, and the CDC's pressure washer safety guidance treats that as a surgical emergency rather than a puncture to bandage. Never run a gas engine indoors — not in a garage with the door open, not in a shed, not under a covered porch, and not "just for a minute to run the fuel out". Carbon monoxide is colorless and odorless and the CPSC continues to record deaths in spaces the victims believed were ventilated. Run the tank dry outdoors, then wheel the machine in.

What it costs versus what it saves

Prices as of mid-2026. The whole winterizing kit costs less than a tank of gas and is the single highest-return maintenance any pressure washer owner can do.

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