there must be something in the water UK /ðɛə mʌst biː ˈsʌmθɪŋ ɪn ðə ˈwɔːtə/US /ðɛəɹ mʌst bi ˈsʌmθɪŋ ɪn ðə ˈwɔtəɹ/ phrase1 •(humorous) There are so many instances of something unusual, such as in people's behavior, that there must be a common cause.