Criteria for Selecting a New Bus Wash System

By Francis Tenggardjaja

The easiest, fastest, and least expensive measure that bus and motorcoach operators can take to make a lasting impression is to keep their vehicles washed and shining. A bus wash system represents a significant capital investment from initial planning to installation. When it comes to selecting the right bus wash system, there are several critical factors to consider:


Size is very critical when preparing a specification. With so many different sized vehicles on today’s market, it is important to know what you are working with. Many large transit operations are only providing services to a single sized bus, but more often than not, you are servicing several different vehicles, all varying in size. Consider the size difference between the largest and smallest vehicle you plan to wash. Generally, a vehicle’s width already has been guided and determined by the Department of Transportation, so the bus’s height is a critical determination.

Number of Vehicles Washed Per Day

The next thing to consider is how many vehicles you want to wash per day. This will dictate the type of equipment needed to support the operation. In most cases, buses are washed when they come in for fueling or dock at the end of day, so there has to be a window of time when all of the buses can be washed at the same time. If you have a three-hour window and 100 buses, 100 buses need to be washed within those three hours.

Selecting Equipment

It’s important to note that some types of equipment have limits on how many vehicles they can wash per hour. This will dictate if you are going to use a drive-through vehicle wash, or a rollover type of vehicle wash. Rollover equipment, which moves backward and forward with the vehicle at a standstill, can only wash 10 to 12 buses per hour. On the other hand, drive-through systems, can wash 30 to 50 buses an hour, depending on the system. Both systems have pros and cons when it comes to the efficiency and effectiveness of the wash.

Space Availability

Space availability is another important consideration. Most buildings have specific height and width limitations within the bay. Newer buses are often much higher than older models, reaching as tall as 14 feet. Ceiling restrictions dictate the size and scope of the equipment that the building can accommodate, which consequently dictates the size of bus that can be accommodated.

Water Quality

Water is another important feature to consider when it comes to the quality of your potential bus wash system. Hard water can result in excessive window spotting, particularly in the Western states, necessitating the addition of a reverse osmosis system to reduce/eliminate spotting. Systems utilizing recycled or reclaimed water often generate bacteria, resulting in an unpleasant odor, which can be controlled by additional chemical treatment or equipment, such as enzyme injection systems and aerator or ozone generators.

Environmental Concerns

When it comes to the wash process, certain equipment requires large amounts of energy to operate, creating very high operational costs. 

These systems also require massive amounts of water being pumped into the system and sprayed during the wash process. This water must be reclaimed, meaning that it must be processed through a reclamation system. The reclamation system will have to process more water if you use a high-pressure system rather than friction. This extra use of water ultimately leads to increased consumption of chemicals and electricity. In the end, a wash using high pressure pumps consumes 8 to 10 times the power used by brush friction.

We also recommend using biodegradable chemicals that are not oil-based, to minimize environmental harm and make it easier for the sewer department to clean up wastewater before it is discharged to the ocean. Another thing to consider is that system structures that use galvanized framing can release unwanted zinc into the wastewater.

The reasons for choosing one system over another run the gamut of variables — space and site considerations, the size of the fleet, allotted time and labor, water usage, water reclamation, and a host of environmental regulations. The key to selecting the right system is taking the time to research what works best for you and your operation.

Francis Tenggardjaja is executive vice president at N/S Wash. With locations across the world, N/S Wash has become an industry leader for efficient and reliable vehicle wash equipment. Visit for more information.