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The water that runs a self-serve site

October 11, 2010
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Water is the most important component of all carwashing equipment when it comes to cleaning cars. Without quality water, the finished product will not be satisfactory to you or your customers.

Setting the stage
There are three stages of water treatment needed to help run a self-serve carwash efficiently.

1. Water Softener

All water entering the wash should be softened. Why is this important? The reason is because most water contains hardness minerals, such as calcium and magnesium.

These hardness minerals are a detriment to a carwash in two main ways:

a) Hardness minerals react with soap to form soap curd. The curd formed during this reaction is soap that is wasted and is unusable for cleaning a vehicle.

Therefore, when using hard water to mix soap additional amounts of soap must be added to achieve the desired cleaning efficiency and shine.

By using soft water rather than hard water, soap savings can amount to 50 percent or more. Over time, this means considerable savings to the owner/operator.

b) Calcium and magnesium both cause lime scaling. This is especially apparent in pumps, boilers, and hot water heaters.

When water is heated, the hard minerals will fall out of suspension and settle as scaling. This causes excessive wear to equipment and results in continual maintenance costs.

By merely softening the water, both of the above concerns are eliminated.

A softer choice
When choosing a softener, there are several items to keep in mind, such as:

  • Use only a metered softener. These units regenerate only after actual predetermined gallons of water have been used. This is a cost efficient unit.
  • If you are open 24-hours-a-day, use a twin alternating type unit. This type of unit has one tank in service, while the other tank is in standby. This unit provides continuous soft water 24-hours-a-day without interruption.
  • Sizing of the softener is also critical.

Sizing includes the following criteria:

a) Hardness of the water;
b) Maximum flow rate of the water;
c) Maximum water usage per day (figuring low pressure and high pressure functions); and
d) Size and water usage of the spot-free rinse system.

Always use a vendor who can calculate the above factors for proper sizing. A unit that is too small may harm your operation, while one that is too big is wasted money.

If you are on well water, the water must be tested for:

a) Hardness;
b) pH;
c) Iron; and
d) Hydrogen sulfide.

The existence of any of these may require additional equipment.

2. Spot-free rinse

Most washes now offer spot-free rinse. The reason is that even though the water may be softened, when a vehicle air-dries, the soft minerals still in the water will cause spotting.

A reverse osmosis (RO) spot-free rinse system removes the soft minerals, so no spotting occurs. This is a final low pressure rinse used to sheet the car and remove any minerals left on the car from the high pressure rinse.

RO units should contain total dissolved solid (TDS) meters so water quality can be monitored. When TDS quantities rise or spotting appears, the membrane on the RO unit will need to be replaced.

System Reclaim
Water reclaim is the third stage.

3. Reclaim water

There are two basic types of reclaim systems:

Mechanical: Mechanical reclaim uses conventional water treatment methods like ozone for odor control, and filtration for removal of soaps, waxes, oils, etc.

Generally speaking, one should be aware of the required maintenance, as well as the percentage of recovery that can be accomplished.

The more water that can be reused means less expense in water consumption and sewer rates.

Biological: Biological reclaim uses the naturally appearing bacteria in the water to consume the soaps, waxes, oils, etc. Special nutrients are fed to drastically increase the amount of bacteria, and also focus them on consuming the wash water contaminants.

Dissolved oxygen from a bubbler system prohibits odor problems. Biological reclaim can recover 100 percent of the wash water used, less drive-off, overspray, and evaporation.

Reclaim systems can save the owner/operator literally thousands of dollars every year, while protecting against shutdowns due to drought or water rationing.

New, old and used
The water treatment portion of a carwash essentially covers new water, used water, and old water.

By sizing correctly and choosing correctly, the owner or operator can protect his/her equipment investment and provide an acceptable wash to the customer.

Not only that, but the owner can save money on chemicals, water and sewer costs.

All the other equipment in a carwash makes the owner money, however the water-related items are things that can save a site money.

When water treatment is done right at a site it makes the wash a win-win situation.

Cary Wise is the general manager for Rowafil U.S.A. Water Reclaim Systems, located in Lakehills, TX. Cary has been in the water treatment industry for 25 years and is also a carwash owner/operator. He can be reached at

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