When Hannah is in the bathtub just before killing herself, we do not hear or see any water running. When the tub overflows as she bleeds out, we see the faucet running.
As Clay gives the tapes to Mr. Porter, he claims that everyone before Mr. Porter knows about what he did. However, Bryce also comes before Mr. Porter and Clay is skipping over him on purpose, so he knows Bryce can't know anything about Mr. Porter's involvement with Hannah's death.