Is having a double outlet right ventricle hereditary?

No. If you have a family history of congenital structural heart disease, then then is a very slight increased risk of some type of congenital heart disease, but the chance of it being exactly the same thing would be very small.
Recurrence risks. The listed risk for a parent to pass any form (not the same) of congenital heart disease to an offspring is 4% & increases to 8% if both parents have any form of chd. There are some rare inherited genetic syndromes that can have a higher rate but none involve dorv.