The producers of this film asked the producers of Scary Movie 4 (2006) if they could use their bathroom set for this film as it was an exact replica of the sets used in Saw (2004) and Saw II (2005). They were given permission to use it.
As with the previous two films, only the actors who appeared in the final scene were given the complete script.
Costas Mandylor's character - Detective Hoffman - is named as a tribute to the first two films' late producer Gregg Hoffman.
Although it appears otherwise, only four prosthetic pigs were used in the "Pig Vat".
Actors Tobin Bell and Shawnee Smith spent several weeks before filming getting to know each other personally so the relationship between their characters would appear believable and real.