Inner tube water polo
Inner tube water polo (ITWP) is a variation of the sport water polo with the important difference that players, excluding the goalkeeper, are required to float in inflatable inner tubes. By floating in an inner tube, players experience less contact and expend less energy than traditional water polo players, not having to tread water. This allows casual players to enjoy water polo without undertaking the intense conditioning required for conventional water polo.
This sport is predominantly played at universities by intramural coed teams, but can also be found in recreational adult leagues. The sport's rules resemble those of water polo, however, with no governing body the rules vary across different leagues. For example, while the winner is determined by the team which scores the most goals, some leagues award one point for a male goal, and two points for a female goal, while others award one for either.
The game was invented in 1969 by now retired UC Davis associate athletic director of intramural sports and sport clubs, Gary Colberg. Noticing how much fun the water polo team was having, Mr. Colberg thought up the idea of using tubes so that people with no experience in water polo could still enjoy the game.
There is no governing body or official rules, but the following details have been derived from a combination of innertubewaterpolo.com and the NYC Social Sports Club’s rules and instructions.
Team Requirements 
- A team consists of 6 players (5 + a goalie, or 6 attackers if goalie is ‘pulled’), but may play with a minimum of 4 players.
- Each team must have a minimum of two men and two women playing at all times.
- Inner tubes – these may be true inner tubes from tires or more pedestrian ones found at any store that sells pool and aquatic toys.
- Nets – These should be the same as water polo nets.
- Ball – These should be the same as water polo balls.
Game Length 
- There are two halves, 20 minutes each.
- The clock runs continuously.
- Teams will change sides at half-time.
- All ties at the end of playing time will be broken by a shootout.
Play Area - Side lines 
- The court is the rectangle formed by the pool walls and (if smaller than full pool) lane lines.
- A ball is considered in-bounds until it makes contact with the pool deck or pool surface outside the boundary area.
- The ball changes possession when it goes out-of-bounds.
- A player may make a play on a ball outside the play court as long as
- The ball is in the air,
- The player's tube is in-bounds, and
- The player remains in their tube.
- Any shot or pass that ricochets off a diving board, backstroke flags or other pool equipment within the court boundary and lands in-bounds is a live ball.
Start of Play 
- To start each half, and after each goal, both teams line up at opposite ends of the pool.
- All players must be in contact with the wall before play begins.
- The referee throws the ball into the center of the pool while simultaneously blowing the whistle to begin play.
- On the official's whistle both teams may paddle their tubes toward the ball.
- Pushing off the wall is legal at start.
Stoppage of Play 
- The referee blowing his/her whistle always signals an immediate stoppage of play and a dead ball. This can be for free throws, fouls, injuries, time-outs, penalties, or any other reason the referee deems necessary.
- The play stops if the ball travels out-of-bounds for any reason.
- teams may substitute when:
- A goal is scored,
- The play ends because the ball went out-of-bounds, or
- A time-out is called.
- A goalie can only be substituted for by someone on the sidelines if the ball is live or by anyone if the ball is dead.
- All players, except the goalie, must sit in a horizontal position, facing up inside the inner tube. A goalie must have at least one body part through the hole in the inner tube at all times. They may also sit in the tube.
- If a player falls out of their tube, the player may not participate in the game in any way.
- Players move with the ball by:
- Pushing it in the water,
- Holding it between their knees,
- Gripping it with 2 hands,
- Gripping it with 1 hand,
- Pressing it against their body,
- Or holding it in their lap.
- A player may not hold the ball completely under the water.
- Players may not deliberately hold the ball to delay the game.
- Referees are often charged with determining who receives the ball as a result of a tied-up ball or other infraction.
Contact Between Players 
- Inner tube to inner tube contact is legal.
- Incidental inner tube to body contact is legal.
- A defending player may touch the ball when it is in possession of an opposing player. This includes swatting the ball out of player’s hand.
- It is legal for a defensive player to try to push the player with the ball out of his tube, thus forcing a turnover.
- Any illegal contact between players will result in a free throw.
Free Throws 
- Free throws are awarded for violations at the point nearest the spot of the infraction.
- During a free throw, the person who starts the ball into play has 3 seconds to pass the ball to a teammate.
- A goal may not be scored until a second offensive player touches the ball after the free throw.
- The defense must provide 2 feet of space from the point of the free throw.
- Free throws are awarded in the following scenarios:
- Any offensive player enters the goalie box.
- The ball goes out-of-bounds.
- Players may not interfere with another player, with or without the ball, in the following manners:
- Dunking, or,
- A ball that goes out in the goal box is given to the goalie for a free throw.
Penalty Shots 
- Penalty shots shall be taken by the offended player at the backstroke flags (if no flags exist, it should be 5 meters or 15 feet from goal).
- No defensive player may be within 2 feet of the shooter.
- If the result of the penalty shot is not a goal, the ball remains in play.
- Exception: The ball is dead in a shoot-out if the ball does not go in the net.
- A penalty shot will be awarded in the following scenarios:
- A defensive player enters the goal box to make a play.
- A goalie abandons his/her tube to block a shot.
- The goalie may not abandon his/her tube in an attempt to block a shot from entering the goal. Remember, they do not have to sit in the tube but rather just have a part of their body in/through it at all times.
- If the goalie leaves his/her tube while blocking a shot on goal, this will result in a penalty shot for the offensive team.
- The goalie may never pass the ball beyond the mid-pool line.
- The goalie may not leave the goal box area during play.
- Once the goalie gains possession of the ball, he/she will have 3 seconds to release the ball.
- A ball in play may be passed back to the goalie. The goalie will have 3 seconds to release the ball.
- A goalie can be pulled for another attacking player during normal substitution times (see Substitutions).
- A goal is scored when a legal shot (taken outside the goal box) completely crosses the goal line.
- A player scoring a goal must remain in his/her tube after the goal is scored or the score will be disallowed.
- A shot taken from inside the goal box will be disallowed and the ball will be given to the goalie for a free throw.
- After a goal is scored, the referee will start play in the center of the pool again (see Start of Play).
- Five players from each team will be selected by the team to shoot (goalkeepers may be one of the shooters).
- At least 2 men and 2 women must shoot. They should alternate.
- Shooters do not have to have been in the pool at the end of play.
- Goalies will be the same as the goalies from the end of play.
- A coin flip or another creative method of determining order will decide which team shoots first.
- Each team has a total of 5 penalty shots and will alternate each shot. No rebounds.
- The referee signals the start of each penalty shot with a whistle blow.
- If the score is tied at the end of the first shootout, a ‘sudden-death’ shootout will ensue.
- Once one team leads after an equal number of shots have taken, the game is over.
- Only players who shot in the first round are eligible to shoot in the second round.
- The gender order established in the first round will be maintained in the second round.
- Teams must have an equal ratio of male to females during penalty shots (i.e., both teams must have either 3 women and 2 men or 3 men and 2 women shooting).
Most leagues have their own rules governing misconduct, flagrant fouls, and other more egregious penalties.
Rec Leagues 
- NYC Social Sports Club
- NYCSSC Pictures
- Vavi Sport and Social Club
- Avon, Colorado Recreational Leagues
- Ripon College
- University of Michigan
- Texas A & M
- Princeton University
- McGill University
- University of California, Davis