Not All Soft Washing Is the Same

Two crews can both say “we soft wash” — but the equipment they run decides how deep it cleans, how high it reaches, and how long the result lasts. Here’s what a real soft wash actually takes.

High pressure is the enemy of any exterior — home or commercial building. Aimed at siding, brick, stucco, EIFS/Dryvit, or a roof, it strips finishes, blows out seals, and drives water behind the surface. That’s why soft washing exists: low pressure plus the right cleaning solution to kill algae, mold, and mildew at the root, so it doesn’t just wipe off and grow right back. (Want the full surface-by-surface breakdown of which method your home needs? See our Soft Washing vs. Pressure Washing guide.)

Here’s the catch: “soft wash” is a method, not a machine. Two crews can both soft wash and be running completely different equipment — with completely different results. And soft-wash gear runs a whole ladder.

The soft-wash ladder — from a $125 add-on to a commercial rig

Most “soft wash” setups sit on the low end of this ladder:

• Downstream injector (~$125). Siphons soap through a pressure washer. It draws a weak ~1% mix — “2%” is mostly a myth — and can’t be turned up or down. You clean with whatever it pulls.
• X-Jet (~$200). A nozzle on the end of the wand. You can mix a little stronger, but there’s no real control — and it sprays chemical all over everything. Messy, not precise.
• Batch mixing. Chemical pre-mixed in a barrel and sprayed as-is. Too weak and it won’t clean; too strong and it’s wasteful and hard on landscaping. No adjusting mid-job.
• 12-volt pumps. A step up, but they push only ~5–7 GPM — and closer to 3 GPM at the trigger. They reach ~15–20 feet and have very little rinsing power.
• Gas pumps (Comet P40 / AR-45). More muscle than 12-volt, but still only about 8 GPM at the trigger — roughly half our flow — and limited on reach and rinse. In our experience, less reliable too.

At the top of the ladder — and what KC Splash runs on every job — is the gas-powered Leon John’s Mo Flo system.

Flow is what actually washes — not pressure

Most people get this backwards. In exterior cleaning, pressure is only a small piece; flow — gallons per minute — is what washes and rinses. Our Mo Flo runs ~15 GPM, roughly double a typical 12-volt setup. Fifteen gallons a minute against five is the difference between a faucet turned wide open and one cracked half-on — same water, completely different cleaning power. Higher flow pushes dirt away, keeps it from settling back, and carries the grime and solution off porous brick and concrete. Pressure spot-blasts one small area; flow cleans and rinses the whole surface.

On-the-fly metering, up to a chemical 100% mix. Brick, stone, and roofs can need about 4% strength or higher to actually clean & kill the growth — and a downstream injector tops out around 1%, so it physically can’t get there. We dial the solution to the exact strength each surface needs, change it mid-job, and even swap in different chemicals for different surfaces. No guessing with a pre-mixed barrel.

It all starts at the top — where others fall short

The growth that streaks a home or building almost always starts up high, then works its way down. If a crew can’t truly reach the top, they can’t fix it — they’re just cleaning what they can get to. Weak setups reach top out around 15–20 feet; to go higher they lean ladders on your gutters or throw water and hope, which usually misses and never rinses. Our Mo Flo throws a soft, high-volume stream up to five stories from the ground, so we wash and rinse the very top and get it genuinely clean.

And for a house or building wash, we reach it all from the ground — even a two- or three-story home — with no ladders leaned against your walls. That’s not small: ladders are involved in roughly 81% of construction-related fall injuries treated in ERs. Where other crews are up on ladders all day trying to reach the top, we keep everyone on the ground and take that risk off the table — for you and for our crew.

The roofing industry itself says: never pressure wash a roof

This isn’t just our opinion. The Asphalt Roofing Manufacturers Association — the companies that make the shingles — says it plainly: never use a pressure washer on an asphalt shingle roof, because it strips the protective granules and can cause premature roof failure. The method they do recommend — a cleaning solution left to dwell, then a low-pressure rinse — is soft washing, exactly what we do. And those black streaks aren’t dirt; they’re a hardy algae (Gloeocapsa magma) that a proper soft wash kills at the root, so it doesn’t wash back in with the next rain.

The part most companies skip: the rinse

This is what actually decides your result. Killing the growth is only half the job — the wash is won or lost in the rinse. Cleaning solution left on a surface is sticky: if it isn’t flushed off, it grabs dust and dirt and the surface gets dirty again faster than before — and dries into streaks on glass and trim. Low-flow rigs can’t rinse; they dribble, and the soap stays. Our Mo Flo rinses at around 700 PSI and 15 GPM — more than double the ~300 PSI and 8 GPM a typical gas soft-wash unit puts out — flushing every trace of soap and grime clean off instead of leaving it to bake back on. Nothing’s left behind to catch dirt, so the clean holds.

We soft-wash everything first — even the concrete

Here’s part of how we clean that most companies skip: we soft-wash first, always. Even a surface that’s going to get pressure washed — like concrete — gets a chemical pre-treat first to break the dirt and growth down before we touch it. It lifts the grime instead of just moving it around, so the final clean is deeper and more even.

Better wash, longer clean — that’s why we warranty it two years

More flow means a complete rinse. Metering means the right strength kills the growth at the root. Real reach means the whole home or building gets cleaned — top included. And soft-washing everything first means the dirt is broken down before we clean it. Put it together and you get a deeper clean that holds — which is why we back every building wash with a 2-Year Building Clean Confidence Guarantee. If streaks or growth come back within two years, we do a targeted touch-up, fast and free. No other contractor in the Kansas City metro runs a Leon John’s Mo Flo — they cost real money, and most won’t make that investment. We did, on purpose.

How it stacks up