Softwashing vs Pressure Washing: Why They’re Not the Same
Mark Cave of SoftWash UK explains why softwashing is not just low-pressure pressure washing, and how chemistry, dwell time, and biofilm removal make it a completely different cleaning method.
He also breaks down when pressure washing is the right tool, why turning down a jet wash isn’t enough, and how understanding the difference can protect surfaces and improve results on site.
Chapter 1
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Mark Cave
Let's clear up a misunderstanding I hear all the time. Softwashing is just pressure washing with the pressure turned down and a bit of detergent added. It isn't. And that belief costs contractors money, damages surfaces, and drags prices down for everybody in this trade.
Mark Cave
I'm Mark Cave, founder of SoftWash UK. Today I want to explain what softwashing really is, how it differs from pressure washing, and why knowing the difference changes the decisions you make on site.
Mark Cave
Let's start with pressure washing, because it deserves some credit. A pressure washer cleans by force. Water leaves the nozzle at often 2,000 to 4,000 PSI, sometimes more, and the physical impact blasts dirt, grime and growth off the surface. On dense, durable surfaces like concrete slabs, commercial block paving and certain hard stones, that works very well when it's done correctly.
Mark Cave
Softwashing works on a completely different principle. The water pressure is low, typically under 100 PSI. Think of a garden hose, or a dedicated 12 volt or diaphragm pump delivery system. The water is not doing the cleaning. It's just the delivery method. The chemistry does the work.
Mark Cave
That chemistry might be sodium hypochlorite mixed with a surfactant, or it might be a residual quaternary ammonium biocide such as DDAC. The surfactant helps the solution wet the surface and cling to it. Then you need dwell time, which means giving the chemistry long enough to act. Algae, mould and lichen live on a surface as a sticky biofilm. Softwashing breaks that biofilm down, sanitises it and lifts it away at a microscopic level. You are treating the living organism, not just wiping off what you can see.
Mark Cave
Now, the question I always get is, why can't I just turn the unloader valve down on my jet wash? Here's the honest answer. When you turn the pressure down, you've changed one number, but you haven't changed the method. You still have no chemistry doing the work and no controlled dwell time. You've simply got a weaker pressure washer. Softwashing is a different approach, not a gentler setting.