Abstract: A rotatable roof gutter system comprises an elongate trough that has a longitudinal axis and an open top end for receiving rainwater therein. A bracket assembly rotatably attaches the trough to a building relative to an eave of a roof of the building. The bracket assembly is configured such that the trough is rotatable about the longitudinal axis between a first position and a second position. In the first position, the open top end faces away from an edge of the eave. In the second position, the open top end is positioned to catch rainwater flowing off the edge of the eave. The system also comprises a moisture detector for detecting rainwater falling onto the roof and a drive assembly operatively connected to the moisture detector. The drive assembly rotates the trough from the first position to the second position in response to rainwater being detected by the moisture detector.