Saving Water by Power Washing
Driving down the freeway with power wash trailers that carry hundreds of gallons of water is becoming increasingly dangerous. Yes, we have on a few occasions seen some people give us the “evil-eye” as if we are responsible for stealing all CA’s water. In case you fell asleep and haven’t woke up since 2014, California is in a drought. This lack of water effects nearly every business and every household, even down to something as simple as not receiving your complimentary water at a restaurant unless you ask for it.
But I write this post to clear up one common misconception. Power washing does not waste water, in fact, it actually saves water! Sounds crazy I know… But we all intuitively know that there are certain things that must be kept clean. A large part of our general public’s health and safety comes from clean and sanitary surfaces. Water plays a huge role in keeping our homes, restaurants, schools, playgrounds and many other public places safe and clean. Governor Brown knew this and listed exceptions for the water conservation bulletin back when it was first created.
The biggest misconception stems from the misunderstanding that power washing “uses” a high volume of water. But in fact, power washing actually uses relatively small volumes of water to accomplish the same task that alternative cleaning methods would use. This is because it compresses water under such high pressure that it aids in it’s cleaning power. For instance, if you compare the average garden hose, if turned on from a hose bib, will flow water at a rate of ~ 10 gallons per minute (gpm) at below 40 pounds per square inch (psi). People measure cleaning efficiency/power by what’s known as Cleaning Units (CU’s). CU’s are a factor of gpm x psi (which really is an oversimplication which undermines our industry). Nonetheless, it still does well to prove our point in that a garden hose’s CU’s are measured around 400 CU’s. A typical industrial grade power washer operates at 4000 psi and ~ 6 gpm. That equates to 24,000 CU’s. That’s about 60x the cleaning power of a garden hose. This is because it takes both pressure (psi) and volume (flow) to clean a surface.
BUT that’s not all, because when you consider the additional advantages of an industrial grade pressure washer, you also need to factor in that it can heat the water. This helps lower surface tensions, thus cutting through stains with greater speed and ease, resulting in less caustic soaps and detergents being consumed to help clean a surface.
Additionally, some professional services (such as yours truly) will have vacuums that can recover the wasted water, filter away oils and greases and process the dirty water to 20 micron so that it is clean enough that it can be reused! Did you read that right? REUSED? Crazy but true, and it’s really not that difficult. Check out some more info on that here.
There’s a lot more to this cleaning stuff, but I can already see your eyes dozing as I talk about the “science of cleaning” and “cleaning units” etc. Blah, Blah, Blah I know. The moral of the story is this, seek first to understand, because this knowledge is powerful and it’s part of what keeps our society safe and sanitary.