The playing area shall be rectangular, and have a length of 35 metres and a width of 23 metres. The ImmediateSurround of the playing area shall be an unobstructed area of water, with where possible a minimum width of 1 metre outside all boundaries. The water throughout the playing area must be still water at least 90 cms deep. There must be a clear height of at least 3 metres without obstacles, and a minimum ceiling height of 5 metres, above the playing area. There shall be a walkway on each side of the playing area kept clear for the referees.