9 Best Detergent for Pressure Washers | One Ounce, Forty Gallons

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One purple gallon that turns into twenty, and covers your whole exterior while it does.

If you want the widest spread of finished cleaner from the smallest jug, this 128 fluid ounce concentrate is the arithmetic winner on the list — it dilutes into up to 20 gallons of working solution and cleans up to 5,800 square feet. Pour it into a pressure washer or mix it by hand, leave it on for 3 to 5 minutes to penetrate, then rinse. No scrubbing is the whole pitch, and it is bleach-free and biodegradable, which matters when you are washing near a garden bed or a gutter that feeds one. It also weighs 8.5 pounds at the jug, so it is a two-hand carry to the driveway.

What owners like most is how broad the surface list is — wood, vinyl, and aluminum siding, roofing shingles, gutters, stucco, brick, masonry, concrete, decks, walkways, pool areas, patio furniture, RVs, boats, and engines all sit inside the declared range. “Works great. I spray it on and watch the gunk fall off the siding,” buyers report, and the dilution math backs the value claim: a gallon mixed goes a long way. For a Saturday driveway or deck, it is the jug to grab.

The trade-off is strength, and it is worth saying plainly. This is a general-purpose cleaner rather than a heavy hitter. Most owners find it does a steady job on everyday dirt, and one blunt note in the reviews sets expectations at “80% clean” on the tougher stuff. On black mold or deep-set staining you will likely want to dwell longer, agitate with a brush, or step up to a bleach-based product. Nothing about it is harsh, which is exactly why it stops short of the brutal jobs.

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The big-jug workhorse for siding, driveways, brick, and wood in one pour.

Zep’s pitch is literally in the name — one bottle for the siding, the driveway, the brick, the wood, and the stucco, no separate products and no switching jugs mid-job. The container holds 172 fluid ounces, roughly 5.09 liters, which is noticeably more liquid per bottle than a standard gallon, and it is labeled unscented with a clean scent note in the specs. Its declared job is removing stains caused by algae, and it is concentrated, so the bottle is meant to be stretched rather than poured neat.

Owners are split on how hard it works, and the split is instructive. The positive camp is enthusiastic — it washes really well, one reviewer reports a whole deck clean in a single cleaning, and another used it on a house, driveway, pool patio, and car with the same bottle. A 74-year-old owner mixes the equivalent multi-purpose cleaner in a soap dispenser for windows, waits 1–2 minutes, rinses, and gets sparkling, streak-free glass with no scrubbing at all. What carries this pick is how many surfaces one bottle covers.

The honest caveat is that “all-in-1” describes the surfaces, not the intensity. It handles general dirt comfortably, but one owner who took it to a deck admits deep grime survived, and the most specific complaint is that it did not shift black mold or green algae even with 2 treatments applied as directed. Another notes not much cleaning power and suggests planning on 2–3 washings. So think of this as the reliable middle-strength soap for surfaces that are dirty rather than ruined.

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Built for one thing: stripping a whole house’s siding clean in an afternoon.

Siding is the biggest surface on your property and the one that eats the most soap, which makes yield the number that matters here. This concentrate makes up to 40 gallons of ready-to-use cleaner, a figure that dwarfs the 20 gallons the Krud Kutter and 30 SECONDS jugs produce, and it is built for pressure washers, foam cannons, or plain manual application. It weighs 8.93 pounds and is made in the USA. The formula is quick and free rinsing — the point being that what you spray on the siding comes off instead of drying into streaks.

That rinsing behavior shows up in how owners actually use it. Spray it on, leave it 20 to 30 minutes so it has time to work into the dirt and mildew, then wash it off and watch the surface come back — on white vinyl siding in central Florida it lifted dirt and mildew easily and left the house looking brand new, with two jugs covering a 2,000 square foot home. Mobile home owners mention no streaks even when the mix is poured heavy, and the standard routine is to pre-wet, spray generously, wait a few minutes, then pressure wash it off.

The catch is that this is not a niche product, and it does not pretend to be. One owner’s blunt verdict is that it is no more impressive than the cheaper counterparts — meaning if you are comparing strictly on cleaning power for a small job, a budget concentrate can feel like the smarter buy. Where this one justifies itself is scale: on a large house or a multi-facade job, that 40-gallon yield and the free-rinsing behavior save you refills and re-rinses, which is real time on a ladder-free afternoon.

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The one that groundskeepers reach for when the runoff lands on grass.

If your pressure washer is parked on a lawn with nowhere for the water to go, the formula matters as much as the cleaning. This gallon mixes with water to make up to 16 gallons of pressure washer soap, is unscented, and carries a bio-friendly formulation. Concrete, patios, and siding are the declared targets — dirt, grime, and mold stains. It is also built for direct-from-concentrate soap systems, so if your machine has that setup there is no bucket mixing at all. At 8.7 pounds it is a comfortable one-hand carry from the shelf.

What owners come back to is dilution economy. At 8 ounces per gallon the mixture looks too thin to do anything, and then it cleans a fence passably even before the pressure hits it. The standout review story is not about a surface at all — it is about the lawn edges, which survive this where heavier pressure washer soaps had killed the grass. For a homeowner washing close to planting beds and turf, that single trait can outweigh a point of raw cleaning power. Several owners also note that thin mixtures handled light jobs fine and the jug went a very long way.

Where it stumbles is the hard stuff. One owner used it on the front of a home and was not impressed with the cleaning power at all, feeling any other multi-purpose cleaner would have matched it. The bottle itself says tougher dirt needs a stronger mix: an owner who upped the ratio to 50:50 from the stated 1:8 saw better cleaning but needed 3 passes to get there. Second-story mold and mildew is the specific weak spot named, and light jobs only is a fair summary of where this belongs.

Briggs & Stratton 6826 is the pick for a gardener’s setup — a driveway, a sidewalk, a fence, and a lawn you would rather not kill — and it asks for patience rather than aggression on the stubborn sections.

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A peroxide-powered concentrate for families who want the deck clean without the chemical fog.

Simple Green’s Oxy Solve trades bleach for hydrogen peroxide, which is the difference between a driveway that smells like a pool and one that just smells like an afternoon. It carries EPA Safer Choice Certified status and is built for wood, vinyl, concrete, brick, and composite surfaces, so the no-harsh-chemical claim sits in the actual product data rather than a sticker. One gallon covers up to 6,400 square feet, and the jug weighs 9.27 pounds. It works in a pressure washer or by hand, and the declared jobs run from decks and siding to driveways and patios.

The ppm-free, low-odor formula is what owners mention first, followed by how safe it feels around children, pets, and the environment. It lifts built-up dirt, grime, and weather stains from wood, vinyl, concrete, brick, and composite just as well diluted in a bucket with a brush as sprayed. One vivid success story involves an outdoor rug that had gone half green over a summer — a single coat, five minutes of dwell, and the pressure washer took it all off on the first try. Peroxide formulas need that dwell time to break deep stains down, so let it sit a few minutes rather than rinsing immediately.

The catch is real but easy to plan around: peroxide is not bleach. Owners who expect industrial-grade bite from it come away disappointed, particularly on gutters and grime that has been building for years. Give it the dwell time, use a stiff broom on tire tracks and oil spots before you rinse, and it does what it promises. Rush it or expect it to dissolve decade-old staining, and you will be reaching for something harsher.

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The bleach-backed option for mold, mildew, and algae that have had years to settle in.

When the growth is green, black, and stubborn, gentle chemistry stops helping. This concentrate is powered by bleach to dissolve discoloration, mold, mildew, algae, oil, dirt, and grime, and it is engineered specifically for pressure washer tanks rather than hand buckets. The anti-corrosive formula is called out as safe for your pressure washer equipment — a genuinely important detail, because bleach left sitting in a pump can chew through seals. One bottle mixes up to 20 gallons, and it is made in the USA with US and imported parts weighing 9.46 pounds.

Dwell time is where this earns its keep — spray it on a cool, shaded surface, let it sit, then rinse. Customers note it living up to that: a three-year-old ground-level deck came back in a single application, green algae gone, the wood looking better than new and needing no staining afterward. Some say it keeps working on the surface weeks after the wash. Apply it cool and shaded rather than in direct sun, because a bleach formula that dries mid-dwell is what leaves streaks behind.

Two practical warnings come with the power. First, it is genuinely bleach-based and will take the color out of whatever it touches — clothes especially, so dress accordingly. Second, effectiveness is the most-discussed subject around this bottle, and opinion splits: on heavy growth it delivers, while on lighter, everyday dirt some owners find it no better than cheaper options and think it is not worth the cost. The residue question splits the same way, with one owner seeing siding that looks brand new and another reporting white streaky marks. Cool surfaces, full dwell, thorough rinse — that is the recipe that keeps it in the first camp.

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One alkaline shot for trucks, RVs, engines, and shop floors that never see a brush.

Touchless means what it says: you spray this on, let the formula loosen the grime, and rinse it off without scrubbing anything. The 32 ounce concentrate is a non-acidic, biodegradable alkaline formula built to lift grease, bugs, mud, road film, and grime, and it runs through a foam cannon, a pressure washer, or a bucket. It is declared safe for ceramic-coated, wrapped, painted, chrome, plastic, glass, and metal surfaces when used as directed, and it goes well past vehicles — engines, wheels, trailers, concrete, tile, walls, and shop floors all sit inside its range.

what separates it from the car-focused soap at the top of this list is the target. That one is for gentle weekly maintenance on a finish you care about; this one is for work vehicles, and the dilution confirms it. Owners have cleaned a truck that had sat unwashed for two years with green dirt and bugs in about 20 minutes using a gallon of solution in a pump sprayer, and another used a foam cannon on a car covered in two months of thick winter salt — sprayed on, five minutes waiting, power washed off looking clay-barred. A vintage cast iron coffee grinder with years of dust and showing surface rust gave up almost all of it when mixed 4:1 with water, revealing the original color underneath. Owners keep coming back to how many different surfaces one bottle handles. Note the pressure requirement: one owner found 1800 psi insufficient for the touchless effect, so strong flow matters.

The honest limit is that “touchless” is not “easy.” Cars that have gone months without a wash still need some light scrubbing, and one owner’s black plastic trim came out worse after repeated attempts rather than better. Water spots are the other recurring note on the paint side. Across owners the pattern is consistent: this is a maintenance and heavy-equipment cleaner that rewards frequent use, not a miracle spray for neglected trim.

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Not a soap on its own — the additive that makes bleach stick, foam, and stop stinking.

This bottle is the category oddball, and understanding that is the whole buying decision. Elemonator is a surfactant — the chemistry that lowers water’s surface tension so a liquid spreads and clings instead of beading off — so it is designed to be paired with your bleach or soft-wash mix rather than used alone. Its formulation is built for bleach compatibility and to boost the pH of the bleach solution, both of which make the mix clean harder. It comes as a 64 ounce, half-gallon container, weighs 4 pounds, and is dosed at just one ounce per gallon of water when downstreaming. At that rate it stretches across dozens of jobs.

The two things owners keep coming back for are the cling and the smell. It foams thick, lifts dirt and grime, and helps the bleach mixture stay on vertical siding instead of running down the wall, which means the solution has time to work. As one review puts it, it helps the bleach “stick to the grime a lil better to rinse off easier.” The lemon scent is the other draw — it masks the harsh bleach odor without replacing it, and several owners describe it as the difference between a job that smells like a chemical bath and one that smells tolerable. The declared clean-up list is dirt, grime, and stains, with one owner confirming it removed all three when used as directed.

Two things to know before buying. First, read the bottle: this listing is 64 ounces, a half gallon, and one owner notes the product photo suggests a full gallon, so check the size on the label rather than the image. Second, it is a helper, not a replacement — on mold and algae, one owner found no major difference between this and plain bleach solution on the actual cleaning, and the primary benefit was the scent and the cling. Some owners find it pricey for what it adds, while others call it worth the cost. If your job is a soft wash and you want the bleach to behave better, that is the trade you are making.