How To Use A Pressure Washer: A Contractor’s Guide

Learning how to use a pressure washer is essential for contractors and homeowners alike. These machines save hours of manual scrubbing by harnessing the cleaning power of pressurized water. With the right setup, they can handle a wide range of cleaning jobs across the United States — from siding and patios to vehicles and industrial equipment. 

In this guide we will break down:

• How a pressure washer works and the science behind water pressures
• The differences between electric pressure washers and gas powered pressure washers
• Tools, materials, and safety gear you’ll need for higher pressure cleaning jobs
• A full step-by-step guide for safe and effective operation
• Key maintenance practices and long-term care
• When to use power washers vs. pressure washers
• Common mistakes to avoid and professional tips
• Environmental impact considerations when using high pressure water

How Does a Pressure Washer Work?

Pressure washers rely on a motor or engine to pump water from a water supply (usually through a garden hose) and force it out through a spray nozzle at high pressure. This pressurized water deep cleans surfaces by dislodging dirt, mold, and paint far more effectively than scrubbing.

• Units of pressure: Water pressures are measured in pounds per square inch (PSI). Higher pressure means more force against the surface.
• Water flow: Gallons per minute (GPM) determines how much water is delivered. Higher GPMs mean faster rinsing.
• Cleaning power: Multiply PSI × GPM for the total cleaning power rating. Contractors should match this to the type of surface they’re cleaning.

According to CNET, understanding PSI and water flow is critical to prevent surface damage. Proper pressure measurements also help avoid wasting water.

What Kind of Pressure Washers Should You Use?

Choosing between electric and gas powered pressure washers depends on your cleaning jobs.

Electric Pressure Washers

• Ideal for lighter jobs like a car wash, patio, or outdoor furniture.
• Typically 1,300–2,000 PSI.
• Use cold water and are quieter, lighter, and easier to store on a reel or kart.
• Ryobi electric pressure washers are popular options for homeowners.
• Require less regular maintenance compared to gas models.

Gas Pressure Washers

• Heavy duty models with 2,500–4,000 PSI.
• Better for siding, driveways, and larger surfaces.
• Gas pressure washer engines require oil changes and fuel refills.
• Stihl pressure washers, including the Stihl RB series, are trusted for contractor use.
• Provide higher pressure, greater mobility, and the ability to clean larger areas.

According to Family Handyman, electric vs gas pressure washer usage should be decided based on job size and material.

Pressure Washing Tools, Materials & Safety Equipment

To safely operate a washer, you’ll need:

• Garden hose connected to a stable water supply
• Spray nozzle attachments for different spray angles (15°, 25°, 40°)
• Detergent and washer soap dispenser for stubborn stains
• Safety gear: goggles, gloves, closed-toe shoes, and hearing protection
• Extension cords (for electric) or fuel (for gas pressure washer)
• Surface cleaners for large patios and driveways
• Ladder extensions or telescoping wands for taller structures

OSHA recommends safety checks before operating high pressure water equipment to avoid accidents.

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Step-by-Step Guide to Using a Pressure Washer

This section serves as a detailed step-by-step guide to using a pressure washer. It also highlights pressure washer tips for beginners and the best pressure washer techniques for contractors.

Step 1: Hook Up the Pressure Washer

• Attach the garden hose to your washer. 
• Check the water tank setup or water supply for leaks.

Step 2: Add Detergent

• Fill the washer soap dispenser with detergent. 
• For car wash jobs or outdoor furniture, specialized soap works best.

Step 3: Select the Nozzle

• Choose the right nozzle based on spray angles. 
• Wide spray angles clean large areas, while narrow ones handle tough stains.

Step 4: How to Start a Pressure Washer Safely

• For electric: Plug in and switch on. Ryobi power models are common choices.
• For gas pressure: Check oil, fill the fuel tank, open choke, pull-start the engine.

Step 5: Best Pressure Washer Techniques for Contractors

• Hold nozzle 6–12 inches from the surface.
• Use overlapping passes for an even finish.
• Wash siding from top down to clean effectively.
• For cars, use low PSI and wide nozzles to clean without scratching.
• Contractors should adjust PSI pressure to match surface PSI limits.

Pressure Washer Tips for Beginners

• Always start with the widest nozzle and lowest PSI, then increase.
• Test spray on an inconspicuous surface first.
• Keep a steady pace; avoid holding the nozzle in one spot.
• Wear hearing protection and gloves for all cleaning jobs.

Step 6: Pressure Washer Safety

• Never spray people or pets.
• Avoid ladders; use extension wands instead.
• Ensure first you’ve turned on the water supply before starting.

Step 7: How to Winterize a Pressure Washer

• Drain water tank and pump.
• Add antifreeze for cold climates.
• Store indoors on a reel or kart to prevent freezing.

For larger businesses, see our How to Start a Pressure Washing Business guide for pricing and operations advice.

Maintenance Tips for Long-Term Use

Regular maintenance ensures your washer delivers consistent cleaning power over time and prevents costly downtime:

• Check hoses and seals for leaks before every use, as even small leaks reduce pressure and efficiency.
• Replace worn spray nozzles to maintain accurate pressure measurements and avoid streaking.
• For gas powered pressure washers, change oil and spark plugs regularly and inspect the air filter to keep the engine running smoothly.
• Flush the system with clean water after each use to prevent buildup of detergents and minerals.
• Keep units stored in a dry, clean place away from direct sunlight or freezing conditions.
• Inspect high pressure hoses and connections every few months for cracks or wear.
• Lubricate O-rings and fittings to reduce friction and extend lifespan.
• Schedule annual servicing for heavy duty contractor use.

Following these steps extends equipment life, reduces the risk of breakdowns during busy cleaning jobs, and ensures your washer consistently delivers the higher pressure and cleaning power needed for professional results.

Power Washer vs. Pressure Washer: What’s the Difference?

While often used interchangeably, there’s a difference that contractors need to keep in mind:

• Pressure washer: Uses high pressure water and is more common for exterior cleaning jobs like siding, patios, and decks.
• Power washer: Similar design, but heats the water for tougher cleaning jobs like oil stains, grease, or chewing gum removal.

Both provide excellent cleaning power, but contractors should select based on surface type, water supply, and the nature of the stain. Power washers are highly recommended for industrial or oily surfaces, while pressure washers are best for general exterior cleaning.

Comparison Table

By reviewing these differences, contractors can decide whether higher pressure alone is sufficient, or if the addition of heated water will make cleaning jobs faster and more effective.

Common Mistakes to Avoid

Even experienced contractors can make errors, especially when working with high pressure water equipment. Here are common pitfalls to watch out for:

• Using higher pressure than needed on soft surfaces like wood siding, which can strip paint or etch the surface
• Forgetting to turn on the water supply before starting, causing pump damage
• Holding the spray nozzle too close to paint, windows, or roof shingles, leading to cracks or leaks
• Not performing regular maintenance such as checking oil, cleaning filters, or replacing worn nozzles, which results in costly repairs
• Ignoring hearing protection and other safety gear, increasing the risk of injury
• Using the wrong spray nozzle angle, which can gouge concrete or leave streaks on siding
• Neglecting to clear debris from the area, allowing objects to become projectiles when hit with high pressure water

Avoiding these mistakes improves results, protects property, and keeps clients satisfied while reducing downtime and repair costs.

Environmental Impact of Pressure Washing

Using high pressure water has environmental considerations. The EPA recommends:

• Using eco-friendly detergents to minimize harm to soil and waterways
• Avoiding unnecessary water waste by matching PSI and nozzle size to the job
• Collecting runoff when cleaning oil or chemicals to prevent contamination
• Educating clients about best practices for sustainable exterior cleaning

By factoring in environmental impact, contractors can provide responsible and marketable pressure washing services.

A Better Alternative for Contractors

Managing invoices and payments is just as important as knowing how to use a pressure washer. With Invoice Fly’s Invoicing Software, contractors can:

• Generate professional invoices for pressure washing services
• Accept payments online
• Track square footage pricing in real time
• Share invoices instantly with clients