Terry Kiser (Bernie)'s stunt double suffered a few broken ribs during filming due to all the pitfalls and stunts of playing a dead man; most notably in the scene involving 'Bernie' being dragged around the surface of the ocean, bumping into metal floating obstacles.
Bernie's house is a real home on the south end of Figure 8 Island near Wilmington, NC and still remains. Many of the movie's scenes were filmed in this area including the waterway at Wrightsville Beach, and the dock and lighthouse scenes at Bald Head Island about 30 miles south.
On the rooftop at Larry and Richard's workplace, Larry sits in an inflatable pool, takes his socks off, and throws them on the ground. The right sock moves, and disappears in one shot.
Bernie is dropped over the side of the deck, next to the house and is later swept out by the tide. Later shots show a dune between the ocean and the house, revealing that the tide does not come up that high.