If your goal is to deliver exceptionally dry cars time and time again, you have to start with a clean car because the cleaner the car is, the better it’s going to dry.

That’s not just sage advice—it’s based on the science behind today’s modern car wash, specifically regarding pH.

Webster’s dictionary defines pH as a measure of acidity or alkalinity on a scale between 0 and 14 with solutions becoming more acidic as you approach zero and more alkaline as you get closer to 14.

Most people envision the path to a clean, shiny car starting with the application of soap, water, brushes and high-speed blowers—and that’s all very valid because it’s essentially true. But what most people don’t realize is that the path to an exceptionally dry car actually starts with the pH of the water and chemicals applied to the car’s surface. If the pH of the water and chemicals used to wash the car are not within a specific range, chances are the car will emerge from the tunnel still wet.

The short-term result will be an unhappy customer. The long-term result could be a dramatic dip in business. You don’t have to be a chemist to consistently produce clean, dry cars but you do have to pay attention to how pH factors into chemical interactions at your wash—and ultimately the quality of your service offering.

Here are a few things to keep in mind to ensure wet cars don’t emerge from the end of your car wash tunnel.

Choosing the Right Presoak

The chemical makeup of the dirt and road film on the vehicle’s surface will determine whether you use a low-pH presoak (acidic) or a high-pH presoak (alkaline) because each can vary on effectiveness depending on whether the contaminant is organic or inorganic.

Generally, low-pH presoaks are effective against typical soils with high mineral content that accumulate on the surface of the vehicle whereas alkaline presoaks tend to be more effective on oily substances. In some cases, a two-step combination using both types is effective depending on the nature of the dirt on the vehicle.

With today’s foamers being so concentrated, it’s important to integrate a product that will neutralize a high-pH presoak because the lower the pH of the car surface, the better the car will dry.

In general, if you use a low-pH presoak, your cars will be drier and shinier.

Know What’s in Your Water

The pH of your water supply plays a critical role in selecting the right combination of chemical products to use in the car wash.

For example, most car washes rely on municipal water supplies that tend to be in the 8 to 9 pH range. Water with large amounts of dissolved minerals and or a high pH can affect how well low pH foam detergents work, reduce foam levels and result in a dirtier car.

Water high in dissolved minerals, however, has a higher surface tension than other types of water making it easier for droplets to blow off the surface of the vehicle—resulting in a drier car.

Make it a point to understand what’s in your water because it will make it easier to match the performance specifications of the chemical products you use and produce cleaner, drier cars.

The Role of Drying Agents

It may seem ironic but too much drying agent can result in wet cars coming out of the car wash tunnel.

How so?

The overwhelming majority of drying agents are made from mineral seal oils which leave a slick when they come into contact with water—just like any other type of oil.

When cars come out of the tunnel wet, many car wash operators react by substantially increasing the amount of drying agent even though it’s likely there’s already too much drying agent being applied.

In many cases, there is some other imbalance with chemistry causing cars to stay wet and it’s actually a good idea to turn the drying agent down, not up.

Back in the early 80s, it was common for up to an ounce of drying agent to comprise the car wash chemical mix. Today, drying agent is measured in milliliters, not ounces. So, it’s easy to imagine how major increases in drying agents can throw the whole chemistry cycle out of balance.

Resist the Temptation to Cut Back on Chemicals During Tough Times

When times get tough, the chemicals are often the first thing car wash operators look to save on. But the more you cut back on chemicals, the worse your vehicles will look and there will be fewer customers that want to come use your car wash.

When you cut corners on chemistry, everything else is affected with the quality of your service. And as quality goes down, income goes down in the long run. Your customers may not notice certain things in your car wash, but they will notice when you’re not using the same amount of foam and their car is wetter when it comes out at the end of the tunnel.

There are lots of factors affecting how dry and clean cars are when they exit the car wash tunnel but when chemistry is right, it’s the best tool you have to get a clean, dry, exciting-looking car that your customers will thank you for.