The "Money Pit" house, owned by the Ridder family in real life, was on the market to be sold when the movie was shooting.
During breaks in filming, Tom Hanks liked to drive around in the vintage Lincoln Model L Series classic car which is featured in the movie.
This was the first film that Tom Hanks worked with Steven Spielberg on. They would become close friends and Hanks would work with Spielberg on many of his products during the following three decades.
For the scene with the bathtub falling two floors down after being filled with water, Tom Hanks does an obnoxious laugh (which sounds like the imitation of a sea lion). This clip of him laughing is commonly used for the "Universal" back-lot tour when the tour guides joke with the visitors.
Actual Hells Angels from a local chapter portrayed the bikers in the movie.