Best Pressure Washer Detergent in 2026: Soaps for Siding, Decks and Concrete
Quick answer: Bob Vila names Sun Joe Heavy-Duty Cleaner best overall, at about $25.50 per gallon. Simple Green Oxy Solve, Karcher All-Purpose and Zep Wood Deck and Fence cover other surfaces. We have not tested them ourselves.
Last updated: October 2026. Pressure alone does not remove grease, algae or mildew. The right soap does much of the work, and the wrong one can stain siding or harm plants. This guide compares seven detergents using Bob Vila’s roundup and Consumer Reports’ testing notes. We have not tested them ourselves.
How did we choose these detergents?
We used products named by Bob Vila and Consumer Reports and grouped them by surface. Bob Vila advises looking for a concentration of about 20:1 or better, which means one part cleaner to 20 parts water or a more concentrated mix.
Which pressure washer soap is best? Quick comparison
| Product | Best surface | Yield / coverage | Note |
|---|---|---|---|
| Sun Joe Heavy-Duty | All-purpose | 1 gal, about $25.50 | Biodegradable, may not remove all grease |
| Kärcher All-Purpose | All-purpose | 1 gal makes up to 20 gal | Multi-surface |
| Simple Green Oxy Solve Total Outdoor | Outdoor | 1 gal makes 21 gal | EPA Safer Choice, no rust removal |
| Zep Wood Deck and Fence | Wood | Up to 5,000 sq ft per gal | Not for painted or stained wood |
| Krud Kutter House and Siding | Siding | Makes 11 gal, 3,200 sq ft | Do not let it dry |
| Zep All-in-1 | General | Makes up to 28 gal | Not biodegradable |
| Simple Green Oxy Solve Concrete | Concrete | 1 gal makes 21 gal | Driveways |
What are the best pressure washer detergents?
1. Sun Joe Heavy-Duty Cleaner: best overall
Bob Vila’s top pick costs about $25.50 per gallon and is biodegradable. Its drawback is that it may not fully remove heavy grease.
2. Kärcher All-Purpose: best concentrate
One gallon makes up to 20 gallons of solution, so it stretches far on larger jobs.
3. Simple Green Oxy Solve Total Outdoor: best eco pick
One gallon makes 21 gallons and it carries the EPA Safer Choice label. It will not remove rust stains.
4. Zep Wood Deck and Fence: best for wood
One gallon cleans up to 5,000 sq ft. Do not use it on painted or stained surfaces.
5. Krud Kutter House and Siding: best for siding
One gallon makes 11 gallons and treats up to 3,200 sq ft. Do not let it dry on siding.
6. Simple Green Oxy Solve Concrete and Driveway: best for concrete
One gallon makes 21 gallons and is tailored to driveways and paths.
7. Zep All-in-1: highest yield
Makes up to 28 gallons but is not biodegradable, so rinse plants well.
What did Consumer Reports find?
Consumer Reports tested Kärcher Multipurpose, Simple Green Oxy Solve, Simpson Heavy Duty and Zep All-in-1. It notes that the last two carry skin and eye irritation warnings, so wear goggles, gloves and boots. It also recommends letting soap soak into the surface and considering a spray bottle for mildew.
How do you choose a detergent?
- Match the surface: wood, siding and concrete each have a specific formula.
- Check biodegradability if runoff reaches lawns or gardens.
- Check dilution: concentrates cost more up front but yield more gallons.
- Use the right nozzle: a low-pressure soap nozzle applies detergent, then switch to rinse.
Common mistakes
Sources warn against household cleaners in pressure washers, incorrect dilution, letting soap dry on siding and forgetting to protect plants. Use a foam cannon for even coverage.
How do you apply soap step by step?
- Wet the surface and cover nearby plants with water.
- Apply the diluted detergent from the bottom up with the low-pressure soap nozzle, so it does not streak.
- Let it soak for the time on the label, without letting it dry.
- Rinse from the top down with a wider rinse nozzle, keeping a safe distance.
- Rinse plants again and store leftover concentrate sealed.
Following the label is the most reliable way to avoid streaks and stains.
Frequently asked questions
Can I use dish soap in a pressure washer?
Sources warn against household cleaners. Use a detergent made for pressure washers and follow its dilution.
How long should soap sit?
Consumer Reports says to let it soak, but not dry. Krud Kutter specifically warns against letting its product dry on siding.
Is bleach safe?
Read the label. Many pressure washer soaps are designed to avoid harsh chemicals, and mixing chemicals is dangerous.
Do I need different soap for hot water washers?
Check each label for hot or cold water use.
Final verdict
Start with Sun Joe Heavy-Duty for general cleaning, then add a surface-specific product for wood or concrete. Always test on a hidden area and rinse thoroughly.
Sources: Bob Vila, best pressure washer detergent; Consumer Reports, pressure washer detergent tests. Related: Best foam cannons, How to use a pressure washer, Best for driveways.
