A standard size 5 water polo ball measures 68 to 71 centimeters in circumference, and a size 4 ball measures 65 to 67 centimeters.
A standard water polo ball varies in size based on the age and gender of the players. Men use a size 5 ball with a circumference between 68 and 71 centimeters. Women and junior players use a size 4 ball, measuring 65 to 67 centimeters. Both professional sizes weigh between 400 and 450 grams.
Official Size Standards
Size 5 is the universal standard for senior men's competitions. It must have a circumference between 68 and 71 centimeters. Size 4 is the regulation size for women's matches, featuring a circumference of 65 to 67 centimeters. Both ball sizes must maintain a weight of 400 to 450 grams when dry to ensure consistent performance during long matches.
Testing and Preparation Methods
Officials and players use various methods to ensure a ball meets professional standards before a match begins. These checks prevent inconsistencies in grip and buoyancy.
| Testing Method | Standard Duration | Primary Metric |
|---|---|---|
| Circumference Test | 5 minutes | 65-71 centimeters |
| Weight Analysis | 3 minutes | 400-450 grams |
| Pressure Calibration | 2 minutes | 8.3-9.7 psi |
Surface and Material Requirements
Water polo balls are manufactured from a high-quality, waterproof rubber material. The outer surface undergoes a specialized buffing process to create a rough, grippy texture. This texture is necessary because a smooth ball becomes extremely slippery when wet. A textured surface allows players to catch, hold, and throw the ball accurately with only one hand. While colors can vary in training, yellow remains the standard for official games to provide maximum visibility against the water.
Internal Pressure Regulation
Proper inflation is critical for the ball to sit at the correct height on the water's surface. For men's balls, the internal pressure should be 8.3 to 9.7 pounds per square inch (psi). Women's balls typically require slightly less pressure, ranging from 7.0 to 8.0 psi. Maintaining these specific levels ensures the ball behaves predictably during high-speed shots and long-distance passes.
- Check air pressure with a digital gauge.
- Inspect the rubber valve for leaks.
- Verify the surface texture for even wear.