Is it normal for only one nostril to be draining blood after a septoplasty?

Hello and thanks for the questions. Yes drainage after of blood or mucous is quite common after septorhinoplasty. It can last for several days and even up to a week. If you develop high volumes of bright red blood I recommend contacting your surgeon. 

Hi and welcome to our forum.
Hi and welcome to our forum!
Congratulations on your recent surgery. The performance of rhinoplasty involves the separation of the
nasal bones and cartilages from overlying and underlying structures,
fracturing the nasal bones, removing excess bone / cartilage, reshaping of
the remaining bone and cartilage. The significant intraoperative
trauma may result in a bit of postoperative bleeding. In our practice we utilize a "drip pad" under the nose secured with tape to catch any accumulating blood. It is usually required for less than a week. If you are fully saturating a 2" x 2" gauze within an hour or so, you should contact your physician. The septal segment of the procedure is usually performed through one nostril which may explain the difference in drainage amounts.
Continue followup with your surgeon.
Best wishes...