It seems funny to me when I hear that doctors and nurses tell their patients not to get their wounds wet for l to 2 to even 6 weeks after surgery. With few exceptions such a skin grafting I encourage my patients to shower the day after surgery. I do not want them getting into a tube an immersing their wounds. Soap and water is what I scrub my hands with before surgery so it should be good for the patients skin after surgery. Actually I encourage the patients to wash their wounds with soap and water and if they have sutures, which most don't, to place antibiotic ointment on their sutures. I especially want them to wash around their drains and apply fresh ointment around the drains at least two times a day.
But if your surgeon wants it another way, more power to them. What works best in each surgeons hands is the best approach.