Originally Posted by AliRulz77
so there are no current plumbing systems in it, when you say use the shell, do you mean put in my own plumbing? I'll google the pex and OEM. Thanks so so much I am starting from scratch and really appreciate it.
This a a cool project. I hope you share your progress on this site!
"In general" a relatively modern travel trailer hooked up to AC power, water and sewer, has essentially the same plumbing as what you would find in a store front retrofitted as a salon. Everything ends up in a municipal sewer or a septic drain field eventually. All the rules that apply to draining hair products in a regular salon would apply to your situation.
Assuming the chemicals you use are the same as used for municipal sewer systems, and that you will always have access to a water supply and a sewer drain, the big difference for what you are planning, is if you will be working while disconnected from a sewer for periods of time. In that case your design point is how mauch capacity your grey/black water tank has.
If you will be permanently hooked up to a city sewer or a septic tank, the big decision you will have is if you want to bypass your black water tank (to avoid "piles") and install a regular flush toilet for your customers.
If you plan to work disconnected and/or be mobile, then you have a little more homework to do regarding water and drain capacity. All very solvable!