When running a mobile car wash rig and handling car dealership accounts, the water quality is paramount. If the water is too hard, it leaves spots, and for new cars being sold to real customers, often paying 10s of thousands of dollars, well, you get the picture. Before retirement, I ran such a mobile car wash franchising system, and even today, I am asked technical questions about how to do it right.
Not long ago, a mobile car washing company owner asked me about; “Water? [Should I use] RO or deionized? [referring to: Reverse Osmosis RO or D.I. as in De-ionizing filters]. I figure a 2000 gallon a day system will cost me about $5,000. De-ionizers I have not yet studied. I plan on carrying 500 gallons on the truck and pulling a nurse tank with 500.
The de-ionize tanks get expensive because you can only use them for so long before they need recharging. You can buy a $12 kit to recharge them yourself, but the problem is there is acid inside of the W filter tank when they need recharging and it has to be flushed out with lots of water, and you cannot do it your house, it’s against the law.
Therefore you have to go to an industrial water company to get them (rent them with deposits), and often they charge you $60 to $90 depending on the area. And, depending on the parts per million of particles in your water at home [or at the shop], they may only last for 900 to 1500 gallons. However, if you get a water softener and/or RO membrane system at your house, you can pre-clean the water before you run the water through your de-I tanks, this gives you very clean water and allows the DI tanks to last for 3000 – 4,000 gallons without recharging.
Indeed, I do recall one time that I rebuilt a water treatment system for a medical blood testing facility, and their system ran the water through carbon filters, salt pellet filters, and then through a robust set of RO membranes and then D.I. tanks, for ultra clean water. After testing that system, I had some water left over and thus, I had filled up about 1000 gallons of water into one of the tanks on one of our mobile car wash rigs, and took the water out to clean car lots after testing it.
Wow, it was amazing and when I used 3000 PSI, it blew all the dirt off the cars and there were zero water spots. I think I cleaned something like 200 cars by myself in an hour and a half. Zero water spots.
The question is how clean do you want to get the water, and how much high-pressure washing/flushing do you want to do, GPM matters for that. But the more gallons per minute you are using, the more your water cost to clean that water. Also the problem with reverse osmosis is it uses two to 3 gallons to make 1 gallon of clean water.
Companies like Starbucks run it through their RO system three times to make the ice and the water to make their coffee, that way you can really taste the coffee, much different than home coffee making with the local minerals also in the water and the smell of the local water too. They are using 7-8 gallons to make 1 gallon of reverse osmosis water, therefore their water bill gets up there, and it really is kind of a waste of water unless you really really need it.
If you talk to others who have experience in this field I bet they concur with much of what I’ve said, and might even have other points to add? Because it depends on what you are trying to do, what you are trying to wash, and the cost reality, of what that job pays. I mean you are in business to make money right?