While blue is a universally popular color, the reason it features so prominently in car wash icons is that it sends a message of cleanliness and trust. That’s why you’ll also see it in many pharmacy logos or on detergent product logos. It is also a color that symbolizes water and oceans, so it makes sense to use it in your car wash logos - an industry where cleaning and water are major features. However, if you do not want to use blue in your logo design, there are many other colors that can do a good enough job. Consider using green, orange, and white. Black and beige are also popular as secondary colors in car wash logo designs.