Water polo's rules are a combination of those of hockey, soccer, basketball and swimming. Teams consist of six players and a goalie, along with alternates or substitutes. Regulation pool sizes are 25 meters by 20 meters for women and 30 meters by 20 meters for men, with a depth no less than 1.8 meters. Physical contact in water polo is acceptable, though fouls of differing severity also apply.
The object of a match is to score points by getting the ball in the opponent's net. Players are obliged to keep the ball in one hand, and they advance through the pool either on their own, keeping the ball in front of them, or through passing with their team mates. The only player allowed to place both hands on the ball is the goalie, as long as the goalie is within 5 meters of the net. Water polo games are divided into four 8-minute quarters, with 2-minute breaks scheduled between each quarter. As in basketball, shot clocks apply to play, though they differ depending on the particular level of competition.
Fouls in water polo are divided into "ordinary" and "major" categories. Ordinary fouls result in a free throw for the affected team, and individual players can accumulate unlimited ordinary fouls within the progress of a single game. Typical ordinary fouls include tipping the ball out of play, touching it with both hands, holding the ball underwater, transgressing the shot clock or delaying the game. Major fouls, on the other hand, often constitute serious violations characterized by aggravated physical contact with another player, which is the reason major fouls are also commonly referred to as "physical" fouls. Punishment for major fouls is usually exclusion from the game for at least 20 minutes and can lead to expulsion.