Most guys think pressure is what cleans a surface. It's not. Chemicals do about 80% of the work. Pick the wrong one and you'll spend twice as long on a job and still get a mediocre result. This guide breaks down every major chemical type, what it does best, and which brands are worth buying in 2026.

The Quick Answer

There are four chemical categories every pressure washer contractor should know:

Sodium hypochlorite (SH): mold, mildew, algae -- the workhorse chemical for most jobs
Alkaline degreasers: grease, oil, and heavy grime on concrete and equipment
Surfactants: not a cleaner on their own, but they make everything else work better
Specialty acids: rust stains, mineral deposits, and efflorescence on concrete

You need at least the first three on every truck. The acids are for specialty jobs that pay 2-3x standard rates.

Sodium Hypochlorite: The Chemical Every Contractor Needs

Sodium hypochlorite -- or SH -- is just bleach in higher concentrations than what's sold at grocery stores. Pool bleach runs 10-12% SH. Household bleach is 3-6%. The difference matters. For professional pressure washing, you want 10-12% SH so you can dilute it down to the right working concentration without using too much product.

Here's the concentration guide by surface:

House wash (vinyl, aluminum siding): 0.5-2% SH mixed with surfactant
Concrete and hard surfaces: 2-4% SH for tougher mold and algae
Roof soft washing: 4-6% SH -- higher concentration, lower pressure (under 150 PSI)

Buy bulk. A 55-gallon drum of 10-12% SH runs about $1.50-$2.50 per gallon from a chemical supplier. At those concentrations, one gallon of SH makes 5-12 gallons of working solution. Buying gallon jugs from a hardware store costs 3-5x more and adds up fast on busy weeks.

Avoid the Big Box Store Products

Products like Krud Kutter and other retail concentrates are built for homeowners -- not contractors running multiple jobs per day. They're not cost-effective at scale. A professional contractor going through 20-30 gallons of solution per day needs supplier-grade SH and a proper mix system, not something from the Home Depot shelf.

Alkaline Degreasers: For Grease, Oil, and Commercial Work

When you're dealing with oil stains, grease buildup, or commercial kitchen exteriors, SH alone won't cut it. You need an alkaline cleaner with a pH of 8-14. These products contain sodium hydroxide, which saponifies oils -- basically turning them into soap so water can rinse them away.

Alkaline degreasers are the standard for:

Restaurant exteriors and dumpster pads
Concrete with heavy oil staining (driveways, gas stations)
Commercial equipment and machinery
Loading docks and warehouse floors

A high-quality alkaline degreaser applied at the right concentration, left to dwell for 5-10 minutes, and then hit with 2,500+ PSI removes stains that would take four passes with SH alone. On commercial jobs where you're charging $0.15-$0.30 per square foot, that time savings goes straight to your bottom line.

Surfactants: The Multiplier Chemical

A surfactant doesn't clean anything on its own. What it does is make your SH or degreaser stick to vertical surfaces longer instead of running off. On a two-story house or a roof, that extra dwell time is what actually kills the mold and algae at the root -- not just bleaches the surface.

Most experienced contractors mix surfactant with SH on every house wash. The difference in results is real. Without surfactant, you get lighter cleaning and more callbacks. With it, the surface stays wet longer, the chemistry works deeper, and the job holds up longer.

Well-known brands contractors actually use:

Elemonator: Widely used, stable with chlorine, citrus scent helps with customer perception
Slo Mo Softwash: Very thick, significantly increases dwell time -- a little goes a long way
Southern Drawl: Designed specifically for soft washing, works with SH-based mixes on siding and roofs
Simple Cherry: Industrial-grade cleaner and degreaser that also functions as a surfactant on some jobs

Add 1-3 oz of surfactant per gallon of working solution as a starting point. Adjust for vertical surfaces and heavy growth.

Specialty Acids: For Rust, Scale, and Efflorescence

This is where specialty pricing kicks in. Standard chemicals won't touch rust stains, battery acid stains, calcium deposits, or the white mineral streaks (efflorescence) that show up on concrete and brick. For those, you need an acid-based product.

Oxalic acid: Best for rust stains and tannin stains from wood decks. Mix 1/2 cup per gallon, dwell 5-10 minutes, rinse. Effective and relatively safe.
Citric acid: Natural option for light descaling, hard-water deposits, and wood deck brightening. Less aggressive than oxalic, good for delicate surfaces.
F9 Barc: A contractor-favorite for heavy rust, battery acid stains, and calcium deposits. More aggressive, but handles stains that nothing else touches. One of the few products that'll remove those orange iron streaks from well water irrigation.
Phosphoric acid: Used for concrete etching before sealing and for heavy mineral scale. Usually diluted to 10-15% working concentration.

Charge a premium for any acid-based specialty cleaning. Rust removal runs $0.50-$0.75 per square foot -- 3-5x standard concrete cleaning. The chemicals cost more and the job takes longer, so the pricing should reflect it.

What to Have on Your Truck

You don't need 12 different chemicals. A well-stocked rig handles 95% of jobs with four products:

10-12% SH in a dedicated tank or 5-gallon jugs from a pool supply supplier
Alkaline degreaser concentrate for concrete and commercial work
Surfactant for mixing with SH on house washes and roofs
Oxalic acid for rust stains and deck brightening (add to your specialty menu)

Total investment for startup chemical inventory: $150-$300 if you're buying in gallon quantities. Drop that to $80-$120 per week once you're buying SH by the drum.

Bottom Line

The guys making real money in pressure washing know their chemicals. They're not guessing -- they match the chemical to the surface, mix to the right dilution, and let dwell time do the heavy lifting before they ever pull the trigger. That's what separates a contractor who can handle any job from one who only does basic house washes.

If you want to take instant quotes on specialty jobs like rust removal, roof washing, or grease cleaning, try QuoteSnap for free. Set your rates by service type and let customers get a price directly on your site -- so you're quoting while you're still on the job.

Best Pressure Washing Chemicals: Expert Comparison Guide (2026)