The invention relates to a rotor blade for a wind power plant comprising a rotor blade body, wherein the rotor blade body encloses a hollow space, wherein the rotor blade body comprises a penetration for draining the hollow space, and a functional element, wherein the functional element is displaceably connected to the rotor blade body and is disposed at the penetration. According to the invention, the functional element can be transferred from a closed position into an open position, wherein the functional element can be displaced purely by translation. Improved drainage is thereby achieved and clogging of the drain is prevented, with reduced noise production.