Hip Rehab

I am hving a hip replacement next week and I was wondering is it necessary to go to re-hab?

Physiotherapy. Here's a site you can check. Good luck with the surgery.
http://www.uclahealth.org/body.cfm?id=47 ...

Some patients are discharged from the hospital to a rehabilitation center and some go straight home. I had both hips replaced in separate firms and have been licensed to go straight home. My "Rehab" took place in outpatient. For the first 2 weeks, a PT and a visiting nurse came to my house 2-3 times a week. After that I went to outpatient PT for about five weeks.
So to answer your question, no it is not necessarily required and site rehabilitation may be at home (it's cheaper that way). Other factors may come into play when the decision is taken. In addition to insurance coverage, there are people who live alone or have no social support system or other comorbidities. All of these can be a decisive factor in whether the patient goes to a rehabilitation center or not.
Your intervention is imminent. Have you been told yet by your surgeon if you go in case of dismissal from the hospital?

Not with the hip. Most people do not need rehabilitation with those more, more to the knees now. They may ask you to do a physical therapy consult, what can be done at the hospital to see how you do after surgery. But in my experience, unless you had problems to move before the surgery, most people do not go home with PT.