The 7 Best Pressure Washer Concentrates

The Oxy Solve Total Outdoor Cleaner Concentrate is Simple Green's flagship pressure washer formula, and it is built to be the one bottle a household keeps on hand for most outdoor cleaning jobs. It draws through a pressure washer's siphon tube or soap reservoir at low pressure, or can be diluted and applied by hand with a pump sprayer for spot cleaning.

The formula leans on hydrogen peroxide instead of bleach, which is the main reason it shows up so often in siding, deck, and driveway routines where bleach runoff would otherwise be a concern for nearby grass or garden beds. Reviewers consistently note that it lifts mildew and general grime from wood, concrete, and vinyl without leaving the bleached, patchy look that stronger chlorine-based cleaners can cause.

The main tradeoff is patience. Like most oxygen-based cleaners, it needs several minutes of dwell time on the surface before rinsing to get the full effect, and set-in stains sometimes need a second application or a quick scrub with a stiff brush rather than pressure alone.

Bottom line: for a household that wants one concentrate that handles siding, decking, and concrete without worrying about bleach damage to plants or trim, this is the safest default choice in the lineup.

• Format: 1 gallon concentrate
• Formula type: oxygen-based (peroxide), bleach-free
• Certifications: EPA Safer Choice certified
• Application: pressure washer siphon, soap reservoir, or hand application
• Surfaces: wood, concrete, vinyl, and more

Wet the surface with plain water at low pressure, then apply the concentrate through the siphon tube or soap reservoir at a low-pressure setting. Let it sit for a few minutes so the peroxide formula can break down mold, mildew, and grime, then rinse at full pressure. For hand application, dilute in a pump sprayer following the label ratio and use the same dwell-and-rinse approach.

Because the formula is bleach-free and EPA Safer Choice certified, it is a reasonable choice for properties with pets, kids, or garden beds close to the cleaning area. It is still a cleaning concentrate, so avoid direct contact with eyes and skin, rinse tools after use, and keep it out of reach of children like any other outdoor chemical.

Adam's Polishes Car Wash Shampoo is built specifically for vehicles rather than general outdoor surfaces, which sets it apart from the multi-surface concentrates elsewhere in this guide. It is pH-neutral, so it will not strip existing wax, sealant, or ceramic coating the way an all-purpose degreaser can.

Run through a foam cannon or foam gun attached to a pressure washer, it produces the thick, clinging foam that detailers use to loosen dirt before it ever touches a wash mitt, which reduces the risk of swirl marks on paint. It also works in a traditional two-bucket hand wash if you do not have a foam cannon.

The tradeoff is specialization. It is not intended for driveways, siding, or general degreasing, and buyers who want the strongest foam results will need to pair it with a dedicated foam cannon attachment rather than a basic pressure washer soap nozzle.

Bottom line: for anyone regularly washing a car, truck, or motorcycle with a pressure washer, this is a purpose-built upgrade over a generic all-surface cleaner.

• Format: 1 gallon
• Formula type: pH-neutral car wash soap
• Best application: foam cannon, foam gun, or bucket wash
• Safe on: wax, sealants, ceramic coatings
• Surfaces: cars, trucks, motorcycles, boats

This shampoo is aimed at car owners and detailers who already treat their vehicle's paint with wax, sealant, or a ceramic coating and want a wash soap that will not strip that protection. It is less useful for someone whose only pressure washing job is the driveway or siding, where a multi-surface concentrate is a better fit.

Add the recommended amount to a foam cannon reservoir following the label's dilution ratio, then apply from the bottom of the vehicle up to avoid streaking dry soap on hot panels. Let the foam sit briefly to loosen dirt, agitate lightly with a wash mitt if needed, then rinse from top to bottom before it dries.

Simple Green's House and Siding formula is the more specialized sibling of the brand's Total Outdoor cleaner, aimed squarely at mold, mildew, and algae stains that build up on exterior siding over a season of humidity and shade. It draws through a pressure washer's siphon tube or soap reservoir the same way the rest of the Oxy Solve line does.

Reviewers who use it on vinyl, aluminum, wood, brick, and stucco report that it noticeably lightens green and black mildew staining without the streaky, uneven look that bleach-based siding cleaners can leave behind, especially on textured stucco.

Directions call for a 3 to 5 minute dwell time before rinsing, and painted trim or older siding is worth checking on a small hidden area first, since the formula is still an active cleaner even without bleach. Set-in stains from several seasons of neglect may need a repeat treatment.

Bottom line: if siding and exterior walls are the main target rather than the driveway or a vehicle, this narrower formula tends to outperform a general-purpose concentrate on mold and mildew specifically.

• Format: 1 gallon concentrate
• Formula type: oxygen-based (peroxide), bleach-free
• Application: pressure washer siphon or soap reservoir
• Dwell time: 3 to 5 minutes before rinsing
• Surfaces: vinyl, aluminum, wood, brick, stucco siding

Being bleach-free makes this a lower-risk choice for siding near landscaping, but it is still an active cleaning formula. Check a small hidden area on painted trim or unfamiliar siding materials first, keep overspray off vehicles parked nearby, and rinse plants that get direct contact during application.

Wet the siding first with plain water, apply the concentrate at low pressure through the siphon tube or reservoir, and let it sit for 3 to 5 minutes so it can break down mold and mildew. Rinse at high pressure working from the bottom up to avoid streaking, and repeat on stubborn areas if needed.

Karcher's Multi Purpose Detergent has a straightforward advantage over third-party concentrates: it is formulated by the same company that builds Karcher pressure washers, so the dilution and soap tank compatibility are tuned for that hardware from the start. It also works through most universal soap dispensers on other brands of machine.

The concentrated formula is rated to make up to 40 gallons of ready-to-use cleaner per bottle, which puts it among the most economical options here on a per-gallon basis once diluted. Reviewers report it cutting through dirt and grime on fences, patios, driveways, and sidewalks noticeably faster than plain water alone.

The fragrance is more noticeable during application than the unscented Simple Green options in this list, which is worth knowing if you are sensitive to scented cleaners or plan to use it near an outdoor living space.

Bottom line: for owners of a Karcher machine specifically, or anyone who wants a concentrated, budget-friendly multi-surface detergent for hardscape cleaning, this is a dependable pick.

• Format: concentrated bottle, makes up to 40 gallons of cleaner
• Formula type: concentrated all-purpose detergent
• Application: Karcher detergent tank or universal soap dispenser
• Surfaces: fences, siding, patios, driveways, sidewalks, concrete
• Scent: fragranced

This detergent makes the most sense for households that already own a Karcher pressure washer and want a detergent designed for that specific soap tank, or for anyone prioritizing a low cost per finished gallon over an unscented formula. If fragrance-free runoff near plants or pets is the priority, one of the unscented Simple Green options is a better match.

Fill the Karcher detergent tank or a compatible universal soap dispenser with the concentrate following the label's dilution guidance, then apply at the machine's low-pressure soap setting. Let it sit briefly on grime before switching to high pressure to rinse.

This is the concrete and driveway specific version of Simple Green's Oxy Solve line, unscented and formulated to target the oil, grease, and tire marks that build up on hardscape surfaces rather than the mold and mildew focus of the siding formula. It uses the same peroxide-based, bleach-free chemistry as the rest of the Oxy Solve family.

Being unscented matters more here than it might seem, since driveway runoff often crosses directly over lawn edges, mulch beds, or a patio dining area, and a fragrance-free formula is less likely to leave a lingering chemical smell in those spaces.

Like the other Oxy Solve formulas, it needs a few minutes of dwell time to work, and genuinely set-in oil stains or tire marks may still need a light scrub with a stiff brush before rinsing at high pressure for full removal.

Bottom line: for a driveway, garage floor, or patio job specifically, this narrower formula is a better fit than the brand's general outdoor cleaner, which is not tuned as tightly for oil and tire stains.

• Format: 128 fl oz (1 gallon) concentrate
• Formula type: oxygen-based (peroxide), bleach-free, unscented
• Application: pressure washer siphon or soap reservoir
• Surfaces: concrete, driveways, hardscape
• Targets: oil, grease, tire marks, general grime

The unscented, bleach-free formula makes it a reasonable choice for driveways next to lawns, garden beds, or outdoor seating areas where fragrance or bleach runoff would be more noticeable. It is still an active cleaner, so keep it off skin and eyes and rinse any overspray from nearby plants.

Choose this formula specifically for concrete, driveways, and garage floors rather than siding or vehicles, where the brand's other Oxy Solve formulas or a dedicated vehicle soap are better matched to the surface.

Karcher's Vehicle Wash and Wax detergent is the company's answer to a dedicated car soap, formulated to pair with its own pressure washers while staying gentle enough for painted vehicle surfaces. It is also, notably, the least expensive bottle in this entire guide.

The wash-and-wax formula is designed to rinse away without leaving residue, which reviewers say helps preserve the original shine on cars, trucks, motorcycles, and boats rather than dulling it the way a harsher all-purpose cleaner can. Like Karcher's Multi Purpose Detergent, it is highly concentrated and rated to make up to 40 gallons of finished solution.

It is a vehicle-only formula, so it is not a substitute for a driveway or siding cleaner, and buyers get the best foam and coverage results when it is paired with a Karcher soap tank or a foam attachment rather than sprayed straight.

Bottom line: for anyone who wants a wallet-friendly, wax-safe vehicle detergent and is not trying to find one bottle that also handles the driveway, this is the best value in the lineup.

• Format: concentrated bottle, makes up to 40 gallons of cleaner
• Formula type: wash-and-wax vehicle soap
• Application: Karcher soap tank, foam attachment, or universal dispenser
• Surfaces: cars, bikes, trucks, boats
• Residue: rinses spot-free, wax-safe

This is aimed at owners who wash a car, truck, motorcycle, or boat regularly and want a low-cost, wax-safe soap rather than a multi-surface cleaner. It is not the right pick for someone whose main job is the driveway or siding.

Fill a Karcher soap tank, foam attachment, or universal soap dispenser following the label's dilution ratio, apply from the bottom of the vehicle upward, and rinse from top to bottom before the soap dries on the panels.

The Sun Joe SPX-APC1G is a general-purpose cleaner and light degreaser sold specifically as pressure washer rated, which makes it a straightforward companion for Sun Joe machines or any pressure washer with a standard soap tank. It is meant less as a specialist and more as a do-it-all option for patios, decks, and outdoor furniture.

Reviewers who use it for routine seasonal cleanup, rather than deep-set stains, describe it as a reliable step up from plain water without needing to buy a separate degreaser for occasional grease or grime.

Because it is not a dedicated oxygen-based mold formula or a wax-safe vehicle soap, it is not the strongest choice for heavy mildew on siding or for washing a car's painted surfaces, where the more specialized concentrates in this guide will outperform it.

Bottom line: for general outdoor cleanup tasks that do not call for a specialty formula, this all-purpose option is a solid, no-frills addition to a pressure washer setup.

• Format: 1 gallon
• Formula type: all-purpose cleaner and light degreaser
• Application: standard pressure washer detergent tank
• Surfaces: patios, decks, outdoor furniture, general hardscape

Pick this when the job is general seasonal cleanup rather than a specific problem like siding mildew or vehicle paint safety. For those more targeted jobs, the Oxy Solve or vehicle-specific formulas elsewhere in this guide are a better match.

As an all-purpose cleaner and degreaser, it is still an active chemical formula. Keep it off skin and eyes during application, avoid spraying directly onto live plants, and rinse tools and hoses after use.