# How to Winterize a Pressure Washer: 7 Steps for Gas, Electric and Hot Water

> A step-by-step commercial guide to winterizing a pressure washer: fuel stabilizer, detergent flush, draining, pump saver, why not to use windshield washer fluid, and a spring restart checklist.

- **URL:** https://janitori.com/blogs/equipment-guides/how-to-winterize-a-pressure-washer

**In this guide**
- [Why winterize](#why)
- [Step-by-step](#steps)
- [Electric and hot-water machines](#electric-hot)
- [What not to put in the pump](#antifreeze)
- [Spring restart](#restart)
- [Safety and wash water](#safety)
- [FAQ](#faq)

To winterize a pressure washer, stabilize the fuel, flush the detergent system, drain every hose, and fill the pump with pump saver so no water is left inside to freeze. Skipping it risks freeze damage to the pump and a machine that will not start in spring.

This guide follows the maker procedures from Mi-T-M and Briggs & Stratton and adds what a commercial fleet needs: a repeatable order of steps, electric and hot-water differences, and a restart checklist for spring.

 **Key takeaways**
- Gas goes stale in about 30 days, and most U.S. fuel is an ethanol blend, so add fuel stabilizer and run the engine for two minutes to circulate it before storage.
- Flush the detergent line with clean water for up to two minutes, release trapped pressure, then disconnect and drain every hose, the gun and the wand so nothing freezes or grows mildew.
- Run pump saver through the pump until the discharge is 100% solution. It protects against freezing, mineral buildup and dried-out seals and pistons, which plain draining alone does not.
- Do not use windshield washer fluid as antifreeze. Mi-T-M warns it contains about 32% methanol, which attacks the carbon steel in machines with coils.

## Why Does a Pressure Washer Need to Be Winterized?

A pressure washer needs winterizing because water left in the pump can freeze and damage it, and fuel left in the tank goes stale over the off season. Both problems show up as a machine that will not start or will not hold pressure in spring.

Briggs & Stratton puts the fuel clock at about 30 days before gasoline goes stale, and notes that about 90% of fuel sold in the U.S. is an ethanol blend that can cause rust, corrosion and gum or varnish buildup in the tank ([Briggs & Stratton winterizing guide](https://www.briggsandstratton.com/en-us/support/maintenance-how-to/winterize-and-store-your-pressure-washer)). On the water side, Mi-T-M says winterizing keeps components from freezing and extends the life of the machine ([Mi-T-M winterizing guide](https://www.mitm.com/blog/winterize-pressure-washer/)).

If a machine will run again within a few weeks, you do not need the full procedure. It is for any unit that will sit through a cold off season, or any unit stored where it could see freezing temperatures.

## How Do You Winterize a Pressure Washer Step by Step?

Work in this order: fuel, detergent flush, release pressure, drain, pump saver, then storage. Doing the pump saver last means no fresh water gets back into the pump afterward.
- **Treat the fuel (gas machines).** Add fuel stabilizer to the tank following the maker directions, start the engine and run it for at least two minutes so the treated fuel circulates through the system, then shut it off.
- **Flush the detergent system.** Put the detergent injector tube in a bucket of clean water and run the machine on the low-pressure setting for up to two minutes. Mi-T-M says leftover detergent should be flushed before storage to avoid mold and mildew.
- **Shut down and release trapped pressure.** Turn off the engine and the water supply, point the gun in a safe direction, squeeze the trigger to bleed the pressure, then engage the trigger lock.
- **Disconnect and drain.** Once the unit cools, remove the garden hose, the high-pressure hose, the gun and the wand. Drain as much water as you can from each, wipe the hose and let everything dry.
- **Empty the pump.** Briggs & Stratton has you pull the recoil handle about six times on its gas units to push remaining liquid out of the pump. Follow your own manual for the equivalent on other models.
- **Add pump saver.** Attach the pump saver bottle to the water inlet, open the valve, and cycle the pump until the liquid at the outlet is 100% pump saver solution. On Briggs & Stratton units, a short garden hose on the inlet adapter and two pulls of the recoil complete the fill.
- **Store it right.** Wipe off dirt and moisture and store the machine in a cool, dry place, with the hoses coiled loosely and the accessories stored with it.

For a fleet, put the steps on a laminated card hung on the machine and have the same person do every unit.

## Does an Electric or Hot-Water Pressure Washer Winterize the Same Way?

Electric and hot-water machines follow the same flush, drain and pump saver sequence, minus the engine steps. Skip the fuel stabilizer on electric units because there is no fuel system to treat.

Mi-T-M's method for an electric machine is to attach the pump saver bottle to the water inlet, open the knob, then squeeze the bottle while turning the machine on until the liquid coming out is 100% solution. On a gas machine the recoil cord does the turning instead.

Hot-water machines add a heating coil, and Mi-T-M's warning about carbon steel coils applies to the antifreeze you choose (see the next section). Always check the manual for any extra coil-draining step the maker requires. Examples in our range include the electric [Pressure-Pro Eagle EE2015G](/products/pressure-pro-eagle-ee2015g-electric-cold-water-direct-drive-pressure-washer-1500-psi-2-0-gpm-115v-1ph-18a-gp-pump), the gas-powered [Pressure-Pro Eagle II E3027HC](/products/pressure-pro-eagle-ii-e3027hc-20-cold-water-gas-direct-drive-pressure-washer-2700-psi-3-0-gpm-honda-gx200-cat-pump) and the hot-water [Pressure-Pro Hot Shot 4012-10C](/products/pressure-pro-hot-shot-4012-10c-hot-water-gas-pressure-washer-4000-psi-4-0-gpm-honda-gx390-cat-pump).

## Can You Use Antifreeze or Windshield Washer Fluid in a Pressure Washer Pump?

Use a product made for pressure washer pumps, called pump saver, and do not use windshield washer fluid. Mi-T-M says windshield wash contains about 32% methanol, which attacks carbon steel and does more damage when heated.

Pump saver is what the makers recommend because it protects the pump against freezing, helps prevent hard-water mineral deposits, and preserves seals and pistons. Briggs & Stratton adds that it prevents rust and keeps pistons and seals from drying out. Buy the pump saver your machine maker specifies, since each maker publishes the product it supports.

## What Should You Check When You Restart a Winterized Pressure Washer?

Reconnect the hoses, run clean water through the pump before starting, and check for leaks at every fitting. Expect leftover pump saver to come out of the outlet with the first water, and catch it in a bucket.
- **Fuel:** if the machine sat longer than your stabilizer's rated storage time, drain the tank and refill with fresh fuel.
- **Hoses and fittings:** look for cracks, kinks and leaking quick-connects before you pressurize.
- **Nozzle:** confirm the right tip is fitted. Our [pressure washer nozzle chart](/blogs/equipment-guides/pressure-washer-nozzle-chart) shows the color and size to use for each job.
- **Soap line:** if you apply degreaser through the injector, such as [Degreaser MAX No.72](/products/degreaser-max-janitori-no-72), confirm the siphon tube and filter are clear before the first job.

## How Do You Handle Safety and Wash Water During Winterizing?

Release pressure before you disconnect anything, keep the trigger lock engaged, and keep flush water out of storm drains. Trapped pressure in a hose can still discharge when a fitting opens.
- **Never point the gun at skin.** A case report on high-pressure water injection injuries notes that early symptoms can be minimal even though the injury is serious, and that the area can become extremely painful and swollen hours later ([PMC, high-pressure water injection injury](https://pmc.ncbi.nlm.nih.gov/articles/PMC2657237/)). Any injection needs emergency care.
- **Unplug electric units before you work on them.** The CPSC has recalled electric pressure washers sold without an integral ground-fault circuit-interrupter because of shock and electrocution risk ([CPSC recall notice](https://www.cpsc.gov/Recalls/2026/Workbless-Pressure-Washers-Recalled-Due-to-Risk-of-Serious-Injury-or-Death-from-Shock-and-Electrocution-Hazards)).
- **Keep flush water and pump saver off storm drains.** EPA stormwater guidance for vehicle and equipment washing recommends keeping wash water out of the storm system ([EPA stormwater BMP](https://www.epa.gov/system/files/documents/2023-01/bmp-vehicle-maintenance-and-washing.pdf)). Collect the discharge in a bucket.

## Frequently Asked Questions

## Do pressure washers have to be winterized?

Yes, if they will be stored where they could freeze or sit unused for a season. Water left in the pump can freeze and cause damage, and untreated fuel goes stale, so makers recommend the flush, drain and pump saver routine.

## Can I put antifreeze in my pressure washer?

Use pump saver, not automotive antifreeze or windshield washer fluid. Mi-T-M warns that windshield wash contains about 32% methanol, which attacks carbon steel. Use the pump saver your machine maker specifies.

## How long can gas sit in a pressure washer before it goes bad?

About 30 days, according to Briggs & Stratton. Ethanol-blended fuel can break down in the tank and cause rust, corrosion and varnish buildup, so add stabilizer and run the engine for two minutes before storage.

## How do you winterize an electric pressure washer?

Flush the detergent line, release pressure, drain the hoses and gun, then attach pump saver to the inlet and squeeze the bottle while briefly turning the machine on until the outlet runs 100% solution. Skip the fuel steps.

## How long does the engine need to run after adding fuel stabilizer?

At least two minutes, per Mi-T-M and Briggs & Stratton, so the treated fuel circulates through the whole fuel system before you shut the machine off.

## Related Guides
- [Pressure Washer Nozzle Chart: Colors, Angles and Tip Sizes](/blogs/equipment-guides/pressure-washer-nozzle-chart)
- [Pressure Washer Soap vs Degreaser: What to Use and How to Apply It](/blogs/equipment-guides/pressure-washer-soap-vs-degreaser)
- [What Is a Good Pressure Washer PSI? A Commercial Job Chart With GPM](/blogs/equipment-guides/what-is-a-good-pressure-washer-psi)
- [Best Commercial Pressure Washer](/blogs/equipment-guides/best-commercial-pressure-washer) [Shop Pressure Washers](/collections/pressure-washers) [Shop Degreaser MAX No.72](/products/degreaser-max-janitori-no-72)