Revealing mistake: In the scene when the main character is in the library on the internet, she goes to a couple of websites. When the shot shows the URL up top, it is C:\windows98\mydocuments\etc.html. Instead of actually searching on the web they used a premade html page and accessed it from their computer.
Continuity mistake: Samara, as seen in the psychiatric sessions on the videotape, has a prominent gap in her front teeth - yet when she decomposes in Rachel's arms down in the well, the skull that is left has perfect teeth with no visible gap.
Factual error: In the scene where Noah analyses the tape, he says that the 'timecode' seems to be invalid and says that every tape has a track where you can see what device was used to record it, etc. The video technology explanation originates from the original, Ringu, with the plot of The Ring changed to make it more applicable to average Americans. But a VHS tape does not have a special track for timecode. It is possible to lay a timecode onto the tape in either an analogue form via a special audio channel, or as digital information on lines 16 and 18 of the vertical interval. But this 'timecode' is only used for professional video editing. A standard VCR, like the one they were playing the tape on, does not use this, and therefore makes Noah's explanation a minute of utter nonsense.
Revealing mistake: When Rachel is racing to save Noah, she is trying to call him on her cell phone. There is a shot of two hands on the steering wheel as the car turns and then a cut to her holding the phone in one hand a split second later while she was talking the entire time, showing that the shot with both hands was a stunt double and not her.
Continuity mistake: In the extra/cut scenes included on the DVD, there is one where Rachel is in Katie's room snooping around. She goes over to the cabinet that has the TV on it and opens the top drawer, rummaging through it. After looking, she closes the BOTTOM drawer even though she was looking through the top one in the previous shot.
Factual error: When Noah drops Rachel off at the ferry he drives right up the the gate at the dock which is strictly prohibited by Washington State Ferries. The only cars allowed in this area are the ones who are boarding the boat, no exceptions.
Factual error: The license plate on Rachel's car is not a valid Washington State license plate, while similar to the very outdated original issue plates, which would have never been issued on such a new car, they are missing tabs on the front which were mandatory on those plates and all Washington plates in 2002 when the movie was filmed.
Factual error: When Rachel and Noah end up back at Shelter Mountain Inn, Noah rips up the floor with an ax. When he tosses the cicle cutout of wood planks, there are no floor joist remnants still attached underneath them. Floor joists are necessary for support, otherwise the floor would not have even held up under the weight of a person walking under them. Also, there would be no point in nailing through the planks if there was nothing to nail into.
Deliberate mistake: When Rachel researches Anna Morgan in the Seattle PI newspaper archives she looks through hardback books. The PI has not only been using microfilm and computer archives for years but archives are available on line at www.seattlepi.com.
Continuity mistake: When Rachel is approaching the top of the ladder upon entering Samara's room at the stable, the camera is following her from behind and it shows her reach the top and wait there for a few seconds, yet when the camera shows a front on shot, she hasn't reached the top yet.
Visible crew/equipment: In the end, when we see the closeup of Samara's eye, you can see several white sheets used to reflect light into her face, as well as the reflection of the camera, in dead center of her pupil.
Continuity mistake: Rachel goes to the lodge reception and the clerk points out the tape collection to her. She turns and is drawn to The Tape in the centre of the shelf. It is lying sloping up to the left, label spine outwards, spools on the left. When Rachel picks it up to drop it into her bag, it is spools to the right, label spine inwards.
Revealing mistake: After Rachel tumbles down the well, we see her heavy-duty Eveready Commander Flashlight, 12-volt battery and all, bobbing above the surface of the water like a cork. Which is ridiculous. A real 12-volt Commander Flashlight would sink like a rock, because it weighs about 4 pounds. However, the filmmakers needed to explain how Rachel could see at the bottom of a pitch-black well, so they used a lightweight, floating flashlight prop, supposedly providing a light source for the scene.
Continuity mistake: Naomi Watts' dark roots change length throughout the movie.
Continuity mistake: When the woman is watching the film and trying to see the lighttower, she has blood in her nostrill even though she has not yet started to bleed.
Factual error: The well in the video is situated on level ground. The Cabin under which it is now supposed to be has been constructed on inclined ground.
Other mistake: The skull they used for the little girl in the well is obviously an adult's skull.
Other mistake: When Samara is falling down the well and we see the approaching water surface from her POV, there is a reflection of Anna looking down the well but no reflection of Samara.
Factual error: In the scene where Rachel is walking in the street looking at the photos she has just collected from the photo-shop, her hands (and the rest of her body) are moving in the natural way. In the shot at the photos taken from behind her you can see the ground moving underneath her but her hands are perfectly stable suggesting she is standing on a moving platform.
Continuity mistake: In the scene where Rachel approaches the horse and the horse starts going crazy, you can see the ring at the end of the rope securing the horse break away from the trailor. In the next sequence when the horse is running around on the barge, the rope is broken with no ring.
Chosen answer: She says "Daddy loves the horses...but he doesn't know" meaning she knows what's about to happen to all his horses. (Because she makes them commit suicide).