The majority of the movie was shot in three locations. The outside of Garth Manor was shot at a mansion in Redlands, California. The inside of Garth Manor was filmed in a residential home in Pasadena, California. The frat party was filmed in an apartment lobby in Los Angeles, California. The mansion used as Garth Manor is now a museum in Redlands, California -the owners made the change from private residence to a museum shortly after filming was completed on the movie.
The film makers had a hard time with the owl who was supposed to fly directly at the camera. They eventually settled with a shot of the owl flying to the upper right of the camera.
The many underground tunnels filmed in the movie were actually no more than two corridors in which the director had the actors running repeatedly through from different angles.
Though the movie required several shots of the actors to run from the front of the house to the front gates, the actual distance between the two is one mile.
For the scene where Jeff is thrown down a flight of stairs and hurt his leg, there wasn't a lot of acting involved. In reality, actor Peter Barton had really hurt himself and most of his limping was due to being in real physical pain.
Several residents of Redlands, California were hired as extras in the film. Kimberly Crest, the mansion in Redlands where much of the film was shot, was also the locale for Fleetwood Mac's 1987 music video, "Big Love". Despite the depiction in the film, Kimberly Crest has no underground tunnels.