Conventional Detergents
For basic cleaning of surfaces that don't require heavy degreasing, conventional household detergents can work well when used in a pressure washer. However, there are important factors to consider for each type:
Dish Soap – Can cut through light dirt but is less effective on grease oil. Only use small amounts diluted with water and rinse well as residue can leave films. Good for surfaces like siding. Dawn dish soap can be used in pressure washers and I was surprised by their performance. You should consider it as a new family cleaning solution.
Laundry Detergent – Formulated for fabrics, not ideal for pressure washing due to potential residues left behind if over-applied. Best used sparingly for light-duty tasks.
All-Purpose Cleaners – Their product may not be optimized for outdoor pressure washing. Check labels for appropriate surface usage.
Pressure Washer Cleaning Concentrates
Formulated specifically for pressure washing, these soaps are more effective at cutting through tough grime like oil, grease, mildew, and dirt. Common types include:
Degreasers – Strong formulas with powerful solvents to emulsify and dissolve greasy residues. Best for engines, machinery, and heavily soiled areas.
Bug and Tar Removers – Designed to lift embedded insect remains and sticky substances like road tar that resist ordinary detergents. Works on car finishes, siding, and decks.
Wheel and Tire Cleaners – High-foaming soap fights brake dust and embedded particles on wheels, tires, and wheel wells.
Difference from conventional soaps: Compared to all-purpose cleaners, concentrates require much less product to do the job. Their specialized chemistries break down specific problem soils that regular detergents can’t handle as well.
Factors to Consider When Choosing
Pressure Washer Type – Gas or electricity impacts soap selection. Gas can utilize hot water cleaners.
Surface Material – Different materials like wood, metal, and concrete require different chemical tolerances. Check product instructions.
Hot vs. Cold Water Usage – Only apply cleaning agents stated as safe for hot water above 105°F when using a heated spray function.
Water Source – Soaps safe for well-soft water may damage surfaces in hard water areas without additives.
Choose Eco-Friendly Soaps
For cleaning pressure washing projects where minimizing environmental impact is a priority, plant-based or sustainably sourced detergents are a good choice.
Biodegradable – Readily breaks down after rinsing, avoiding polluting runoff. Safer for lawns, gardens, and waterways.
Vegetal-based surfactants – Clean effectively using ingredients from coconut, citrus, or other crops versus petrochemicals.
No toxicity – Gentler chemical makeup poses minimal risks to wildlife and humans. Child and pet safe.
Organic certification – Means formulated without harsh chemical fragrances or dyes. Better indoor and outdoor respiratory health.
Safety Precautions
While soaps help with cleaning, it's important to take safety measures:
Wear protective gear – Goggles, rubber gloves, and boots protect skin/eyes from spray and chemicals.
Use hot water carefully – Soaps labeled for use under 120°F to avoid burn risks. Know your machine's heat limits.
Good ventilation – Work on windy days if possible for chemical fumes or use a mask in enclosed areas.
Nozzles reduce splash-back – Lower pressure fittings like spray wands mitigate spray mist accidents.
Conclusion
Choosing the appropriate soap for pressure washing comes down to understanding the cleaning needs, water source characteristics, environmental factors, and safety considerations for the project at hand. By taking the time to select the soap tailored to the job, homeowners and contractors alike can safely and efficiently clean exterior surfaces.
