The use of a salon shampoo bowl is intended to make the task of washing hair more efficient and comfortable for both the salon client and the salon worker. However, maximum efficiency and comfort can only be achieved with salon bowls that are the correct height.
Each shampoo bowl is unique in its design. The individuality of each bowl lets salon owners and workers design their salons in a style that is all their own and provide a desired atmosphere to the salon. Thus, each bowl has to be installed at the height for which it is designed. For most bowls, this is between 33 inches and 36 inches, so even if you don't have the manual for your bowl, don't plan to go beyond this range unless it is exceptionally clear that installing the bowl within this range is not suitable for the bowl design.
Look at whether the bowl you are installing has adjustment options. Hydraulic shampoo bowls may be raised and lowered significantly (some models may be raised or lowered up to a foot). This means that having the bowl installed beyond the normal 33-to-36-inch range may not be a problem for some models. If you're considering installing an adjustable bowl, look at the manufacturer's guidelines and then consider what height would result in the most minimal adjustments during use.
Clients and Workers
Your clients should not be leaning back very far in the styling chair. If they are, it means that your salon bowl needs to be raised. Ideally, the bowl should be positioned at a height that allows just a slight lean while the client remains primarily upright so that water and other chemicals can run easily into the basin.
Once you are sure that the bowl height will allow clients to sit only in a semi-reclining position at most, look at how the majority of the workers in the salon work over the basin. If they are slouching forward to reach, then the basin is not tall enough. They should be able to stand fairly straight while working. A combination of adjusting the bowl height and the chair height should be able to accommodate most people.
Every locality has its own plumbing regulations. You may need to check whether the angle of piping created by the height of your specific shampoo bowl is in agreement with these regulations. If the angle doesn't allow for gravity to drain the pipe properly, then you may need to find a way to raise the bowl height (e.g., a concrete or marble salon bowl platform).