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Can You Use Hot Water in a Pressure Washer? When?

Pressure washers that use hot water are often said to improve efficiency. You see professional cleaners use them. The question for many is whether you should use hot water. Are there certain situations where hot water pressure washers are better or can you also use cold water in your pressure washer.

You can use hot water in a pressure washer specially if you are trying to clean up grease, oil, live cultures of mold and mildew. But be sure to use a pressure washer that is designed to use hot water. Using hot water to clean is very similar to washing dishes where hot water dissolves oil faster.

Cold water pressure washers are good for general cleaning on surfaces with dust, dirt and grime.

To better understand this question it’s good to first look at a simple scientific explanation of what heat does to molecules. After this, I’ll share some scenarios when it’s appropriate to use a hot water pressure washer. From the examples, hopefully you’ll be able to better determine what specific cases you would use hot water over a cold water pressure washer.

Understanding the Science

Heat causes water molecules to be more excited and to move around more than if they were when cold. When water molecules move more, there’s an increased chance they collide with other molecules from other substances. The effect is the solute substance becomes more solvent, dissolving in the process.

A good real life example that I think most people can relate to is the use of hot water to wash oily and greasy bowls and plates. Have you tried running cold water from the kitchen sink and washing dirty tableware with it? It’s not very effective. What DOES work is hot water. Get my point?

Hot water is able to break up and dissolve solute molecules.  Cleaning solutions and the act of agitation take cleaning a step up. You can say that the role of agitation, such as from hand scrubbing, helps further break molecular bonds, and that soaps and detergents help dissipate the molecules away.

Cleaning Any Oil or Grease Stained Surfaces

Cleaning an oil or grease stained surface with a pressure washer can be challenging with cold water. I don’t want to say it can’t be done. It just might take a little longer than you might plan for. But using hot water in your pressure washer will speed things up.

One common application is for oil stains in garages or on driveways. Working on a car or parking a leaky car on a driveway is a common occurrence. Accidents happen and the easiest way to clean up these nasty stains is with hot water and a pressure washer.

Of course, if you can find and use an appropriate soap or detergent, that would be even better. Any multi-purpose pressure washer detergent will work. There are also ones that are designed specifically for concrete. If you use a degreaser before pressure washing that’s a bonus for sure.

Killing Live Cultures

The presence of mold and mildew is a serious problem. These live cultures can cause an assortment of health issues. If you have mold and mildew growing on your house siding you need to remove it as soon as possible.

Usually people use some sort of bleach or white vinegar solution to kill mold and mildew. Unfortunately, it’s not recommended these solutions be used inside your pressure washer due to their corrosive nature. However, there are pressure washer detergents formulated specifically to kill mold and mildew.

If you’re unsure of what to do, just go old fashioned and do a hand scrub to kill the areas with mold and mildew. After that, do a hot water pressure washing to remove whatever residuals there are on the house siding.

Cleaning Construction Equipment

The equipment used on construction sites such as excavators and digging machines go through a great deal of mud and grime. Through repeated use, mud and grime both become caked-on to the equipment. 

If a person washed the equipment with cold water, it might never become clean. Hot water removes the grime and hardened mud quickly and easily making the cleaner’s job much easier. Frustration can be avoided by using hot water pressure washers on the construction site when cleaning the equipment.

Cleaning Restaurants and Wineries

Kitchen surfaces inside of a restaurant get very greasy and various types of stains often set in on certain areas. Restaurants must pass inspection by the health department so a hot water pressure washer must be used to keep surfaces clean. Some surfaces that must be cleaned with a hot water pressure washer are kitchen hoods and ducts and other kitchen surfaces, outdoor seating, dumpster areas, and waste areas.

Wineries have a great deal of equipment that must be cleaned regularly and must pass health department inspection as well. Poor wine quality will be the result of poorly cleaned equipment. Most of the equipment will have to be cleaned with a hot water pressure washer.

Winery Equipment Requiring a Hot Water Cleaning

  • Tanks and fermenters
  • Distillation stills
  • Bottling equipment
  • Food grade hose
  • Food grade pumps
  • Wine presses
  • Grape sorting tables
  • Corkers
  • Wine tanks

Cleaning Rental Property

The exterior surfaces of rental property can become very grimy and greasy over a period of time. Most hot water pressure washer units can be transported in the back of a truck or on a trailer unit. Decks and driveways of rental property often need grease and grime removed. 

Rental property that is used for vacationing must be kept clean to attract tourists. Periodic vacancies might keep rental property from being overly dirty, but driveways and decks might still become gritty. 

Business owners who rent the buildings will need to invest in the use of hot water pressure washers whether it’s by rental or purchase. Keeping outside surfaces clean not only attracts clients, but it also keeps a business relationship with the landlord pleasant.

Cleaning Various Manufacturing Equipment

Manufactured products often leave messes on floors and other surfaces. Depending on the types of goods being manufactured, various types of tools are used. Saws, milling pieces, clamps, and threading tools are just some of the pieces that will need to be kept clean. Many of these parts are small or have areas that are difficult to impossible to reach by hand. 

Cleaning Food Manufacturing Plant Equipment

Food and beverage manufacturing plants have government regulations. Meat processing plants have some of the greatest potential for unsanitary issues. Hot water pressure washers are a must in these facilities and all other manufacturing plants. 

Certain food products can bring cross contamination if surfaces are not cleaned. Spills can cause food particles to become lodged in cracks and crevices. Of course, daily cleaning is a must, but hot water pressure washing is eventually required. 

Food and build-up of other particles can cause equipment not to function properly. Light, daily sanitizing should take place along with pressure washing. 

Cleaning Drug Manufacturing Plant Equipment

Another type of risk for cross-contamination and contamination by bacteria and other microorganisms is in drug manufacturing plants. Drug manufacturing plants are also government regulated. Cleaning measures have to be adhered to. 

If spills occur with certain liquids or pills leave behind residue on surfaces, cross contamination can be a serious issues. Contamination from drug particles could exacerbate illnesses and disorders and cause allergic reactions. Along with other sanitizing practices, large pieces of equipment are washed with hot water pressure washers. 

Cleaning Waste Management Equipment

Equipment such as recycling trucks and garbage trucks pick up everything which includes some of the most vile and unsanitary products. Hot pressure washers must be used to remove grease, mud, and other particles effectively. 

Waste Management Equipment that Must Be Pressure Washed

  • Grinders
  • Shredders
  • Incinerator equipment
  • Landfill tractors
  • Transfer stations

Cleaning Automotive Parts

Although most people do not give thought to auto parts and engines needing cleaned, both build up grease, oil, and grime while in use. Not only is excessive build up unsightly, it can negatively affect the overall function of any automobile or transportation trucks. 

A trucker, mechanic, or vehicle owner will be more likely to spot a crack or other issue with an engine if it is clean. Certain parts under the hood must be cleaned as well in order to quickly spot repair issues and prevent build up from blocking essential function.

Cleaning Automotive Manufacturing Plant Equipment

Like other manufacturing plants, automotive manufacturers have equipment that must be pressure washed in hot water. Various assembly work produces dust and a build-up of chemicals. Not only is cleaning essential for the smooth function of the equipment, it is necessary for employee safety.

No business owner wants an injured employee. Even workers who are well coordinated are capable of slipping on grease or oils that might spill on floors. Regular use of the hot water pressure washer not only keeps surfaces clean, but it also prevents safety issues. 

Final Thoughts

Using hot water to pressure wash is a great way to clean things. It’s even more effective when the surfaces are stained with oil, grease and live cultures (mold and mildew). That’s not to say that you shouldn’t wash with cold water ever. But if you can, use hot water with your pressure washer.

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