Abstract: The present invention relates to cooking oven (10) with an oven cavity (20) and a steam cooking arrangement. The steam cooking arrangement comprises a water reservoir (22) for storing water, at least one steam generator (18) connected to the water reservoir (22) and provided for heating up and vaporizing the water from the water reservoir (22), and at least one steam nozzle arranged at a wall of the oven cavity (20) and provided for inducing steam into said oven cavity (20). The steam cooking arrangement comprises further at least one steam pipe (24) interconnected between the steam generator (18) and the steam nozzle and provided for conveying steam, a water drain valve (30) provided for emptying the water reservoir (22), and a water drain conduit (26, 28) interconnected between the water reservoir (22) and the water drain valve (30).