What was the interplay between plumbing and the routines of audience behaviour at London's eighteenth-century opera house? A simple question, perhaps, but it proves to be a subject with scarce evidence, and even scarcer commentary. This article sets out to document as far as possible the developments in plumbing in the London theatres, moving from the chamber pot to the privy to the installation of the first water-closets, addressing questions of the audience's general behaviour, the beginnings in London of a ‘listening’ audience, and the performance of music between the acts. It concludes that the bills were performed without intervals, and that in an evening that frequently ran to four hours in length, audience members moved around the auditorium, and came and went much as they pleased (to the pot, privy or WC), demonstrating that singers would have had to contend throughout their performances with a large quantity of low-level noise.