Dr. Kelso lives in a house in California.
When Enid was alive, she lived with him. He didn't much like going home because Enid was there, but it was his home. His house had a back yard, where he and Dr. Cox would have beers when Perry became the Chief of Medicine. ("My New Role")
One night, Turk finds Kelso still at the hospital very late, and he finds out that Enid threw him out six weeks before then. She "wheeled in and she caught Kelso hitting on her speech therapist." ("My Hard Labor"). However, after Enid eventually passed away, it seems clear that Kelso was able to return to his house.