Pressure Washing Doesn't Always Need That Much Pressure

 Even some of the tasks that most people think of as "simple" or not-too-hard kinds of projects, like power cleaning, still take some knowledge and skill to do well.

One of the biggest mistakes one can make in power cleaning or pressure spraying, is using too much pressure.   In this case, depending on the surface, there actually is such a thing as too much power.

In fact, for most projects,  you don't really need that much pressure or you damage the surface. Which defeats the purpose. 

Not only does actual PSI matter, dispersal is also just as important.   That's what the various tips or nozzle settings are for.  They disperse the pressurized water flow in a pattern that focuses or spreads the flow in a particular way.

For example, you can use lower actual PSI but if used in a 0 degree nozzle/setting, it puts the flow out with almost no dispersal.  The force is supplied to a very direct point.  Having the effect of maximum pressure but over a very small area.

Proximity is important.   How far you hold the tip away from the surface.  The closer it is, the more of the applied force is maintained.  The further from the surface, the less that force is maintained.   So if you need a lot of applied pressure, but have to be several feet away, you may need to increase PSI.

If you can be right at the surface, you can dial down the PSI, with the appropriate dispersal setting, and achieve the same results.

Using a cleaning solution also affects the pressure.   Using a good cleaning solution breaks down the dirt or whatever is the problem on the surface.   That reduces how much pressure is actually needed.  

All pressure with direct dispersal is just a brute force approach one needs to use with care.  High pressure damage is always something you want to avoid.   Using detergents,  cleaners, brushes and other aids can all help reduce unnecessarily high pressure being applied.