I am not sure there is any set rule on this, however in our company, we have a clear explanation of what is hot tub service and what is maintenance. Hot tub service is also known as hot tub repairs. It’s the service of a hot tub that is not functioning correctly. Weather the hot tub is not heating, the pump is making an unusual noise, the lights don’t work correctly, etc.
On the flip side, hot tub maintenance, is maintaining the water clarity and sanitation. Hot tub service is focused on the functionality of the spa where as maintenance is the water. There is cross over however, water maintenance depends greatly on filtration. The filters and proper water flow will impact water clarity. When hiring a maintenance technician to service your hot tub, it’s critical that the tech understands the functionality of the spa and how all the parts go hand in hand. Water chemistry and proper maintenance is a science!