Professional Carwashing & Detailing

Water conservation for conveyors

October 11, 2010
With throughputs in excess of 110 vehicles per hour, the conveyor tunnel is capable of washing more cars than any other carwash system — and also of using more water than any other carwash system. Carwashes of this caliber can consume well over 60,000 gallons a day, meaning more than 1.2 million gallons a month.

The cost of water and sewer can be the difference between profit and no profit, and in some cases, losses. Often, the charges for water are stepped up with use. The more you use, the more they charge.

Reducing water use
Virtually every component in a conveyor wash requires water. Proper management of these systems and their uses is critical in addressing economical, as well as environmental issues. These systems include:
  • Prep guns;
  • Pre-soak;
  • Under carriage;
  • Wheel/side blasters;
  • Mitters and wraps;
  • Chemical mixing and applicators;
  • Wax and drying agents;
  • Rinse arches; and
  • Spot free rinse system.
Reducing water use is much like going on a diet. You want to lose the weight, but you don’t want to sacrifice your eating habits or go through the day feeling hungry. In a carwash, you want to reduce water use, but you don’t want to sacrifice wash quality or have your customers feel like you are cutting them short.

To reduce water use without decreasing wash quality, you first need to examine and address the carwash’s big water users. For example, the spot-free rinse (RO) system. RO systems are usually desirable in express exterior tunnels to lower labor costs. On the other hand, if you have employees hand drying vehicles at the end of the wash, then a spot-free rinse system may not be necessary.

The drawback of the spot-free system is it uses a lot of water. For each gallon of spot free water used, there are typically two gallons of “reject water” that go down the drain. If 10 gallons are applied to rinse the vehicle, you actually have used (and paid for) 30 gallons of water. Obviously, this can have a huge impact on water use — and your bill.

The “reject water” from a spot-free system is still good clean water. Yes, it will contain more minerals and impurities than fresh water, but it is still clean and suitable for use in your wash process. Capturing and reusing this water for other processes is not only a good idea, it’s fairly easy and inexpensive to do. A simple holding tank and re-pressurization system will allow you to reuse this water in wash or rinse applications that don’t require spot-free. Not only are you reusing the water, you have also cut the water demand for the other functions that are using fresh water — a double whammy.

Another area that can use a lot of water is the rain arch. These arches are typically very liberal when it comes to rinsing a vehicle. You can reduce water use of this unit by as much as 50 percent by installing spray tips which will use less volume at a higher pressure to obtain the same results. The same holds true for your undercarriage wash system.

The number one way to reduce
If you want big savings, you’ll need a more drastic system — water reclaim. When done correctly, this alone can offer up to a 70 percent reduction in water/sewer use. Of course, there are substantial costs and some maintenance associated with a reclaim system, however, these costs can usually offer return on investment in a short period, especially when using large volumes of water.

Not only that, but many municipalities are requiring a water reclaim system before even considering permitting approval, and recycling water is sometimes a necessity for those with limited water or sewer. Even if your municipality does not require a reclaim system, having one can win over community approval by appealing to environmental sensitivities.

Above and beyond water and sewer reduction, recycling water with a reclaim system can offer very substantial reductions in sewer hook-up fees, water main requirements, discharge limitations and can even offer immunity to carwashing restrictions in drought stricken areas.

Recycling in a conveyor tunnel doesn’t have to be all or none. Properly installed, you can pick and choose the functions you want on fresh water as well as the ones you want on reclaim water. It is common for conveyor tunnels to use reclaim water for only the prep guns, undercarriage and/or side (wheel) blasters. These functions use quite a bit of water and do not require a pristine water quality. This alone can offer 30-50 percent reduction in water use for the entire wash. Often times, a smaller reclaim system and tank design can serve these functions, meaning less up-front investment.

For those who desire more savings or reduction in use/discharge, extending the reclaim water into more wash processes may be attractive. This is possible, but you will probably need a larger, more advanced reclaim system.

Reclaim and save
There are many reclaim systems and processes available on the market today. It’s important to shop around for a reclaim system that will best serve your needs.

Whether you are making a large investment on a new carwash or trying to lower your operating cost at your existing facility, it would behoove you to incorporate a good water reclaim program. If your water and sewer are more than $1,000 a month, it’s time to start looking at some options.

Water has become in issue for almost everyone on this planet in one way or another. Using our resources wisely is the responsibility of each and every one of us. With that said, I think I’ll go jump in my swimming pool.

Dean Taylor is the vice president of CATEC Water Recovery and Ozone Systems in Sarasota, FL. His background includes engineering, design and development as well as sales, installation and training for carwash water reclaim and ozone systems. Taylor can be contacted on the internet at