No tea is actually drank in "Tea at the Treedome" until the very end, where Sandy puts the teabags in SpongeBob and Patrick's new water helmets, which turns the water into tea. Prior to this, Sandy invites SpongeBob over to her treedome for tea and cookies.
In "Grooming Gary," while SpongeBob is checking Gary's "Slime Viscosity," he runs through Squidward's house and the latter is shown drinking tea.
In "House Fancy," Squidward drinks tea at the beginning of the episode, and spills it when he's shocked at the sight of Squilliam appearing on the show of the same name. He later refers to it as the "hideous stain on the rug."