Picked from manufacturer specs and manuals; we haven't tested these units.
Use only detergents labeled for pressure washers, and follow the label for dilution, protective gear and disposal. Pick by surface: car, concrete and driveway, house and siding, or deck. Your washer's manual says whether to use the soap tank, the soap tip or a foam cannon. Test on a hidden spot first, and never mix with bleach or other chemicals.
Pick a car wash soap for the way your washer applies soap: a foam cannon or the washer's detergent system. Follow the label.
Detergent
Car wash soap for a foam cannon
In the maker's words "For a High Foam Touchless Wash, add 1 to 3 oz of Honeydew Snow Foam to a 32 oz solution tank of foam cannon or gun."
Who it suits Car washing with a foam cannon.
Trade-off It's dosed for a foam cannon or foam gun tank, so you'll need one that fits your washer.
Check price on AmazonSpec source: manufacturer, checked 2026-10-18.
Detergent
Car wash soap for a detergent system
In the maker's words "9.558-146.0"; "Highly concentrated – one gallon makes up to 40 gallons of ready to use Vehicle Wash."; "compatible with all Kärcher Home & Garden pressure washers, as well as consumer pressure washers made by other brands"
Who it suits Washing cars through a washer's detergent system.
Trade-off It's made for vehicles; for other surfaces, look at the all-purpose and house picks.
Check price on AmazonSpec source: manufacturer, checked 2026-10-18.
For general outdoor cleaning through your washer's detergent system. Follow the label for dilution.
Detergent
All-purpose detergent concentrate
In the maker's words "Designed for pressure washers, but can also be used manually"; "Dilute 1-measure of Simple Green with 10-measures of ambient water"; "Test pressure washer for surface compatibility, with and without the cleaner, in an inconspicuous area."
Who it suits General outdoor cleaning with a washer's detergent system.
Trade-off It's a concentrate, so dilute it as the label says.
Check price on AmazonSpec source: manufacturer, checked 2026-10-18.
Detergent
All-purpose detergent
In the maker's words "Highly concentrated – one gallon makes up to 40 gallons of ready to use detergent."; "compatible with all Kärcher Home & Garden pressure washers, as well as pressure washers made by other brands"
Who it suits General outdoor cleaning.
Trade-off Follow the label for dilution and use, and test on a hidden spot first.
Check price on AmazonSpec source: manufacturer, checked 2026-10-18.
Simple Green facts about the two formulas, for reference: the current Oxy Solve House and Siding Cleaner page says "Mix 1-measure of Simple Green Oxy Solve with 20-measures of water in a bucket" (Simple Green), and the older formula's 2015 safety data sheet says "Dilute 1:10 for manual or pressure washer application to home exteriors" (Simple Green SDS). Your bottle's label decides.
Zep's House & Siding concentrate (not listed here) says "Do not mix with bleach or any other chemicals as hazardous reaction may occur" (Zep).
Detergent
House and siding wash
Who it suits House siding and exterior walls.
Trade-off Simple Green has sold more than one formula under this name, with different directions, so follow the label on the bottle you receive.
Check price on AmazonSpec source: manufacturer, checked 2026-10-18.
It means the maker says the product is for use in a pressure washer. Several washer manuals say not to use household detergents, and some say dish soap clogs the detergent system (see the FAQ). Product wording below is quoted from each maker, not our own claims.
We haven't listed a detergent labeled for concrete yet. Pick one the maker labels for pressure washers and for concrete, and follow the label. Simpson says its Multi-Purpose Cleaner (not listed here) can be used "with pressure washers, directly on surface or with soap injection" and to "always consult your machine's owner's manual for specific instructions regarding use of detergent" (Simpson).
We haven't listed a deck cleaner yet. Use one the maker labels for pressure washers and for wood decks. Kärcher's decking guide says to "only use the flat jet nozzle" on decks (Kärcher). Test on a hidden spot first.
Your washer's manual sets the method. Some washers have an onboard tank or a siphon, some use a soap tip, and some a soap bottle or foam cannon. Simpson's soap guide says "never use bleach or flammable solvents" (Simpson). Sun Joe's SPX3000 manual says: "Do not use acids, bases, solvents, or any flammable material in this product." See foam cannons and the soap tip.
Several manufacturers say not to. Westinghouse's manual says: "Using thicker detergents, like dish soap, will clog the chemical injection system." Champion's manual says the same. Westinghouse's ePX3100 manual says: "Dish and laundry soap is too thick and will clog the nozzle of the detergent bottle." Greenworks and Sun Joe manuals say not to use household detergents. Use a detergent labeled for pressure washers, as your manual specifies.
Detergents the maker labels for pressure-washer use, matched to the surface you're cleaning. Follow the label and your washer's manual.
The soap tip is black on most manuals we read (Sun Joe SPX3000, Westinghouse, Simpson, Generac, Champion), but some washers use a foam cannon or soap bottle instead. Check your manual. See nozzle colors.
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