How to Winterize a Pressure Washer for Storage
Identify the exact gas, corded, or battery model; flush detergent; relieve pressure; drain every water-side part; then use only the pump, fuel, and battery storage procedure in its manual.
Winterizing a pressure washer means removing detergent and water from the machine’s water path, protecting the pump by the exact manufacturer procedure, and putting its fuel, cord, or battery in the specified storage state before freezing weather or a long idle period. The job starts at the model label. A gas washer with a recoil starter, a corded electric washer with a water-flow sensor, and a battery washer may share a hose and spray gun, but they do not share one safe pump-purging method.
The reliable sequence is identify, flush, stop, cool, depressurize, drain, protect, label, and store. Briggs & Stratton’s current general guide tells owners to flush a detergent injector with clean water at low pressure for two minutes, drain the components, pull the recoil handle about six times, and use pump saver. A current Generac gas manual gives a similar recoil procedure for that covered model, while Generac’s 2300 psi electric manual has no recoil step and specifies alcohol-free RV antifreeze for its pump. Those are examples of why the manual controls, not universal instructions.
Do this before the storage area can freeze and before a planned idle period reaches the manual’s long-term threshold. Generac manuals use more than 30 days for the examples cited here. My view: a five-minute model-and-manual check is more valuable than buying every product labeled “winterizer.” The wrong fluid or wrong way of drawing it into the pump can turn preventive work into the damage you meant to avoid.
The short answer
To winterize a pressure washer for storage, identify the exact model and manual, flush the detergent path with clean water, shut the machine down by its instructions, let a gas unit cool, release trapped spray-gun pressure, disconnect and drain the supply hose, high-pressure hose, gun, lance, nozzles, and tank, then prepare the pump exactly as that manual directs. Gas models also need the engine maker’s fuel-storage procedure; removable-battery models need the battery maker’s charge and temperature rules; corded models need a dry, undamaged cord and GFCI plug. Store the dry machine and accessories protected from freezing, moisture, ignition sources, and damage. Do not copy a recoil-cord, antifreeze, pump-saver, dry-running, fuel-draining, or battery-charge step from another model.
Cost and effort
Plan the practical side
| Machine or condition | Water-side preparation | Separate energy or engine step | Manual question that decides the method | Do not improvise |
|---|---|---|---|---|
| Gas, recoil-start cold-water washer | Flush detergent through the specified low-pressure path, stop, cool, relieve pressure, disconnect, and drain every listed component | Use the exact engine fuel and oil storage instructions; handle fuel outdoors away from ignition | Does this model call for recoil pulls, a named pump protector, a short inlet hose with alcohol-free RV antifreeze, or another procedure? | Do not start or run the engine without the water supply when its manual prohibits it; do not assume every pump is serviceable |
| Corded electric cold-water washer | Switch off, unplug as directed, shut off water, relieve pressure, disconnect, drain, and follow the electric model’s pump-storage section | Inspect cord and GFCI plug from the outside and store them dry without sharp bends | Does the manual permit a brief purge, require a named pump product, specify alcohol-free RV antifreeze, or require frost-free storage only? | Do not pull a nonexistent starter, energize a dry pump, or copy a gas-model method |
| Removable-battery washer | Remove the battery when directed, then drain the intake line, hose, gun, lance, nozzles, and internal water path by the exact model procedure | Follow the battery and charger manuals for storage charge, temperature, inspection, and charger connection | Must the pack be removed? What charge range and storage temperature does its maker specify? | Do not invent a universal 50 percent charge, warm a cold pack by force, open it, or leave a damaged pack in service |
| Hot-water, belt-drive, commercial, onboard-tank, or unfamiliar machine | Treat coils, tanks, bypass circuits, reels, injectors, and pumps as model-specific systems | Follow separate burner, engine, electrical, battery, and fuel instructions | What must be circulated, displaced, drained, serviced, or kept full, and who is authorized to do it? | Do not apply a consumer cold-water checklist to a heating coil or unfamiliar pump |
| No readable label or reliable manual | Drain only the user-detachable accessories after safe shutdown and pressure relief | Leave fuel, battery, wiring, and internal pump work unchanged until identified | Can the manufacturer or authorized service provider identify the unit from photographs and serial information? | Do not choose antifreeze, pump saver, oil, fuel treatment, or purge method by appearance |
| Planning line | Published reference | How to use it |
|---|---|---|
| Owner winterization supplies | $25–$50 and about 30 minutes in Angi’s pressure-washer winterization guide | Treat this as a broad consumables-and-time reference. Buy only the exact pump product, connector, fuel treatment, container, and protective equipment approved for the model; tax and local disposal are separate. |
| Residential electric replacement comparison | $100–$700 in Angi’s gas-versus-electric pressure-washer guide | Use the exact current model, pump, hose, accessories, warranty, service access, and cleaning need. A low retail price does not prove replacement is better than a model-specific storage service. |
| Residential gas replacement comparison | $300–$1,000 in the same Angi guide | Compare against a written diagnosis and repair scope, not a guessed failed pump. Include engine and pump condition, pickup, parts, labor, test run, and warranty. |
| One-day rental fallback | $50–$250 per day, with a $90 national average in Angi’s 2026 rental guide | This can be a fallback while a machine is serviced or replaced. Add transport, deposit, fuel, detergent, surface accessories, damage terms, and safe operating time. |
| Checkpoint | Pass evidence | If it does not pass |
|---|---|---|
| Identity | Full model, power source, engine or battery family, manual URL, and storage section saved | Stop before selecting fluids or a purge method; contact the maker or authorized service |
| Detergent path | Specified tank or siphon path flushed with clean water for the manual’s time and pressure setting | Do not leave mixed cleaner in place or combine chemicals; use the label and manual for disposal |
| Pressure released | Machine and water are off, gas unit is cool, gun points safely, trigger was squeezed, and lock is engaged | Keep connections in place and follow the shutdown section; do not loosen a pressurized fitting |
| Accessories drained | Hose, gun, lance, nozzles, tank, and detachable fittings are empty, dry outside, inspected, and loosely stored | Replace damaged pressure-rated parts; do not patch a high-pressure hose |
| Pump prepared | The exact named product and model procedure were completed and written on the tag | Do not substitute fluid or force it through; arrange authorized service if the method is unclear |
| Fuel, cord, or battery resolved | Manual-specific state is documented without leaks, damage, heat, swelling, corrosion, or unknown fuel age | Move people away from a fuel leak, isolate damaged electrical or battery equipment, and use the proper service or disposal route |
| Storage and restart card | Dry protected location, no ignition-source conflict, accessories supported, cover only after cool, and spring steps attached | Choose another location or a qualified storage/service option before the first freeze |
Identify the exact machine before buying a storage product
Clean only enough of the accessible label to photograph it. Save the model, serial information, manual, and separate engine, battery, or charger instructions. Confirm whether it is gas, corded electric, or battery; cold- or hot-water; supplied from a garden hose, tank, or siphon; and fitted with detergent tanks, an injection tube, a hose reel, or accessories that hold water. Search the manufacturer’s support site and the CPSC recall database. Record a dated search result rather than writing “not recalled,” because notices and identifiers can change. If the model cannot be identified, do not pick a pump product from a shelf by connector size alone.
- Find the controlling pages
- Mark shutdown, after-each-use, long-term storage, pump protection, fuel storage, battery storage, high-pressure hose inspection, approved fluids, and spring startup. Engine and pressure-washer manuals may both apply to a gas model.
- Check the idle threshold
- Do not assume winterization begins on a calendar date. Use the expected temperature in the actual storage location and the manual’s long-term idle period. The cited Generac gas and electric manuals direct owners to storage preparation after more than 30 days.
- Classify unfamiliar equipment
- Hot-water coils, onboard tanks, commercial pumps, burners, belt drives, permanent plumbing, and trailer units can retain water in places a portable cold-water checklist never reaches. Route those systems to their manual or qualified service.
Flush detergent while the machine still has its required water supply
Read the cleaner label and machine procedure before mixing, draining, or disposing of anything. Remove unused detergent only by the method the instructions permit. Then flush the designated tank or injection path with clean water at the required pressure setting and for the stated time. Briggs & Stratton’s general storage guide uses a pail of clean water at low pressure for two minutes. That is a cited Briggs procedure, not permission to run every machine for two minutes. Keep the normal water supply connected and flowing whenever the model requires it; a pressure-washer pump can be damaged by dry operation.
- Keep cleaners separate
- Never combine leftovers to save space. Read each product label for disposal, rinsing, personal protection, and surface-water restrictions. A storage drain is not automatic permission to discharge cleaner onto soil or into a storm drain.
- Include detachable soap equipment
- Flush model-approved foam cannons, siphon tubes, filters, and removable tanks separately when their instructions call for it. Dry and label the pieces so a blocked detergent path is not discovered at spring startup.
- Stop for abnormal behavior
- End the flush for a fuel or water leak, damaged cord, hot-plastic odor, smoke, severe vibration, erratic pressure, bulging hose, coupling movement, or a pump that is not receiving adequate water.
Shut down, cool, and relieve trapped pressure in the stated order
Use the model’s shutdown sequence. Turn off the engine or motor, close a fuel valve only when directed, turn off the water supply at the specified point, and let a gas engine and hot surfaces cool. Keep the high-pressure hose connected while the system remains pressurized if the manual requires it. Point the gun away from people, animals, glass, vehicles, electrical equipment, and anything that could be damaged; squeeze the trigger to release trapped pressure; then engage the trigger lock. High-pressure water can penetrate skin. Any suspected injection injury needs immediate emergency medical care even if the opening looks small.
- Electric isolation
- Switch off and unplug a corded model by the plug, not the cord, when instructed. Keep wet hands away from the plug and receptacle. Do not defeat a GFCI device or use a damaged cord for one last purge.
- Battery isolation
- Remove the pack only after shutdown and only as the tool instructions direct. Stop for a swollen, cracked, leaking, wet, unusually hot, impact-damaged, or burned-smelling pack. Do not charge it to see whether it recovers.
- Fuel boundary
- Handle gasoline outdoors in approved containers, away from smoking, flame, pilot lights, switches, chargers, heaters, and hot equipment. Never loosen a fuel cap or drain fuel from a hot or running engine.
Drain the hose, gun, lance, nozzles, tanks, and water-side fittings
After pressure is relieved and the system is in its safe disconnected state, remove the garden hose and high-pressure components in the order shown in the manual. Lay a long hose straight on a safe slope or raise successive sections so water can move toward an open end without kinking it. Drain the gun and lance in the orientations their maker shows. Remove and drain nozzles and detachable tanks. Wipe components dry and inspect the full high-pressure hose for cuts, abrasion, bulges, leaks, crushed areas, stiffness, and coupling movement. Replace a suspect hose with the required pressure rating and connection type; do not repair it with tape, glue, clamps, or a splice.
- Do not forget low points
- Hose reels, quick-connect bodies, spray guns, turbo nozzles, surface cleaners, inlet screens, detergent caps, and short manifold sections can hold water. Drain only by their documented owner procedure.
- Support the hose
- Store a clean, dry high-pressure hose in a loose coil with no tight bend at a coupling. Keep it away from sharp edges, sunlight, vehicle traffic, chemicals, and rodents.
- No compressed-air shortcut
- Do not attach shop air unless the exact manufacturer instructions provide the fitting, pressure, connection point, sequence, and personal protection. Unregulated air can damage seals or eject water and debris.
Prepare the pump exactly as the manual describes
Now follow one pump procedure, the one written for the model. A Briggs & Stratton guide tells owners of applicable recoil-start machines to pull the recoil handle about six times after draining, connect its pump-saver method at the inlet, and pull twice more. The cited Generac gas manual also uses approximately six pulls and names Generac Pump Shield, with an alcohol-free RV-antifreeze alternative and a short hose for that model. The cited Generac electric manual instead directs owners to empty remaining liquid and winterize with alcohol-free RV antifreeze. These examples cannot be blended into a universal recipe. Use only the approved product, quantity, connector, orientation, and action.
- Do not run dry by habit
- Some electric manuals permit only a very brief purge; others specify a fluid-displacement method or frost-free storage. Energizing an unsupported pump without water can damage it. Do not press the switch merely because another guide says to bump the motor.
- Do not substitute automotive antifreeze
- Use only the pump protector or antifreeze type named by the manufacturer. Automotive coolant has different toxicity, material, handling, and disposal concerns and is not a generic replacement for alcohol-free RV antifreeze or a named pump product.
- Stop when the path is unclear
- A seized recoil, blocked inlet, leaking pump, cracked housing, unknown previous fluid, missing adapter, or instruction that conflicts with the installed pump is a service question. Forcing product through is not proof of protection.
Put gas fuel, electric cord, or battery storage on its own track
For a gas washer, read both the washer and engine storage sections. The cited Generac gas manual says fuel stored more than 30 days can go bad; for its covered engine it describes fresh fuel stabilizer circulated by a two-minute run, or draining untreated fuel into an approved container and running until the engine stops. That method belongs to that equipment and must occur outdoors with the required water supply during operation. Another engine may specify a different fuel, tank level, carburetor drain, oil service, storage period, or prohibition. For corded equipment, clean and dry the cord and GFCI housing and stop using any damaged plug or jacket. For a removable battery, use only the battery maker’s storage charge, temperature, charger, and inspection rules.
- Old fuel is not restored
- Stabilizer is preventive. Do not assume adding it to unknown, contaminated, or stale fuel makes that fuel suitable. Ask the engine maker or qualified service provider how to identify and dispose of the fuel lawfully.
- No universal battery percentage
- Lithium battery systems differ. Store the pack at the maker’s stated charge and temperature, with terminals protected, away from moisture, metal objects, children, heat, and ignition. Do not leave it on a charger unless the manual explicitly allows that storage mode.
- Do not open service boundaries
- Do not remove a pump cover, carburetor bowl, electrical housing, GFCI plug, battery case, or control enclosure unless the exact manual clearly places that work in owner maintenance and you can meet every safety step.
Choose a dry protected location and attach a restart card
Store the cool, dry unit upright or in the orientation specified, protected from freezing, rain, snow, direct sun, corrosive chemicals, impact, and unauthorized use. Keep gasoline equipment and approved fuel containers away from heat and ignition sources under local fire rules. Do not place a cover on a hot machine; Generac’s gas manual specifically warns against it. Support accessories so couplings are not loaded and keep nozzles together in a labeled container. The restart card should name any product left in the pump, the fuel or battery state, removed parts, unresolved defects, manual link, and the date.
- Spring water comes first
- At recommissioning, inspect the pump, hoses, cord, plug, battery, gun, lance, nozzles, seals, fittings, and frame before supplying energy. Connect the correct water source and purge or flush storage product exactly as the manual says before starting the engine or motor.
- Controlled first test
- Test outdoors in a clear area with the correct water flow and a low-risk nozzle or pressure setting specified by the manual. Watch for leaks, pulsing, abnormal sound, damaged spray pattern, heat, odor, fault lights, or a hose that changes shape.
- Keep it out of service when evidence changes
- A freeze exposure, cracked fitting, leaking pump, damaged high-pressure hose, stale or leaking fuel, electrical damage, swollen battery, repeated trip, or abnormal first run needs model-specific service before cleaning work resumes.
Put the guide to work
Field notes
- Record the full identity
- Photograph the product label and record brand, complete model, serial range where relevant, power source, engine model on a gas unit, battery family on a cordless unit, pump type if the manual names it, and the manual URL.
- Mark the storage state
- Attach a dated tag stating whether detergent was flushed, the pump product and method used, fuel was treated or removed by the manual, a battery was removed and where it is stored, and what must happen before spring startup.
- Keep the pressure boundary
- A stopped machine can retain high pressure. Keep the hose and gun connected while the system is pressurized when the manual says so, point the gun in a safe direction, squeeze the trigger to relieve pressure, and engage the trigger lock before disassembly.
- Replace, do not patch, a pressure hose
- Generac’s electric manual says a high-pressure hose with cuts, leaks, abrasion, bulging, or coupling movement must be replaced with one meeting or exceeding the unit’s rating. A tape or clamp repair is not a storage fix.
Common questions
Frequently asked questions
- How do I winterize a pressure washer for storage?
- Identify the exact model and read its shutdown, after-use, pump-storage, and fuel or battery sections. Flush detergent with clean water by the approved method, shut down and cool the unit, point the gun safely and relieve trapped pressure, drain every listed hose and accessory, prepare the pump with the exact product and procedure, resolve fuel, cord, or battery storage separately, then store it dry and protected. Do not copy a recoil, antifreeze, or dry-purge step from another model.
- Do I need pump saver in a pressure washer?
- Use pump saver only when the exact pressure-washer or pump instructions call for it and use the named or approved product. Some manuals specify a branded pump protector; some specify alcohol-free RV antifreeze; some rely on a different drain or frost-free storage procedure. Pump saver is not a universal fluid, and the way it enters the pump is also model-specific.
- Can I use RV antifreeze to winterize a pressure washer?
- Only if the model manual permits it, and match the stated type. The cited Generac gas and electric manuals specify alcohol-free RV antifreeze in their covered procedures. That does not authorize it for every washer. Do not substitute automotive antifreeze, mix products, or guess at concentration, amount, connector, or disposal.
- How do I drain water from a pressure washer pump?
- First follow the shutdown sequence and relieve trapped pressure with the gun pointed safely. Drain the detachable hose, gun, lance, nozzles, and tanks. Then use the exact pump step in the manual. Some gas models use a stated number of recoil pulls; some electric models have a different procedure. Never run a pump dry or apply compressed air unless the maker expressly provides that method.
- Should I leave gas in a pressure washer over winter?
- Use the engine and washer manuals. For one cited Generac gas model, fresh stabilized fuel can be circulated through the system, while untreated fuel is drained into an approved container and the engine is run until it stops. Other engines can differ. Do all fuel handling outdoors away from ignition and with the water supply required for any engine run. Stabilizer does not restore stale fuel.
- Can I store a pressure washer in an unheated garage or shed?
- Only if its pump and every water-holding part have been prepared for the temperatures that location can reach and the manufacturer allows that storage environment. A roof alone does not prevent freezing, condensation, fuel hazards, rodents, or damage. A dry frost-free location is safer when the manual requires it.
- How should I store a battery pressure washer?
- Remove the pack if the tool instructions say to, inspect it without opening the case, and follow the battery maker’s exact charge, temperature, charger, and periodic-check rules. There is no safe universal storage percentage or temperature for every chemistry and pack. Keep terminals protected and stop using a swollen, cracked, leaking, wet, impact-damaged, unusually hot, or burned-smelling battery.
- What should I do before starting a winterized pressure washer in spring?
- Read the storage tag and manual first. Inspect pressure-rated parts and the energy source, restore the required water supply, flush or purge the storage product exactly as directed, then add fresh approved fuel or the inspected battery only when appropriate. Test outdoors at a low-risk setting. Stop for leakage, pulsing, abnormal noise, odor, heat, damaged spray, battery faults, or electrical trips.
Use the findings
Open the detailed check for what you found
Make the next step useful
Put this guide on your home plan
Know when to call a professional. Stop if work involves active gas leaks, damaged service wiring, structural movement, unsafe heights, suspected contamination, or a problem you cannot confidently isolate.
Editorial review and sources
Reviewed by: Smart Homeowners Editorial Desk
Last reviewed: October 14, 2026
Original Smart Homeowners editorial; not adapted from a third-party article.
- Briggs & Stratton — Winterize & Store Your Pressure Washer
- Generac — Gas Pressure Washer Owner’s Manual G0066021
- Generac — Electric Pressure Washer Owner’s Manual G0088880
- U.S. Consumer Product Safety Commission — Recalls
- Angi — How to Winterize a Pressure Washer
- Angi — Gas vs. Electric Power Washer
- Angi — Pressure Washer Rental Cost (2026 Data)
