Chapter 3: Indoor Competition Basin

FIMP Code of Competition & Technical Handbook · 2026–2029 Edition (in force from 1 January 2026)

Article 3.1: Dimensions

1. 3.1.1The Indoor competition basin shall be 25.000 m long and 12.500 m wide, with a tolerance of +0.010 m / -0.000 m in each dimension.
2. 3.1.2The water depth shall be no less than 1.35 m and no more than 1.40 m across the whole basin, so that every athlete can stand.
3. 3.1.3The basin floor shall have a gradient of no more than 0.4%.
4. 3.1.4Lane ropes, anchors and backstroke flags shall be removed before competition.

Article 3.2: Water

1. 3.2.1The water temperature shall be 27.4 °C ± 0.2 °C, measured at 14 points and three depths (0.10 m, 0.70 m and 1.30 m) no more than 60 minutes before the first heat of each session.
2. 3.2.2Free chlorine shall be between 1.0 and 3.0 ppm. pH shall be between 7.2 and 7.6.
3. 3.2.3Water hardness shall be recorded but is not regulated. Readings above 240 mg/L CaCO₃ shall be reported to the Water Quality & Thermal Commission.
4. 3.2.4Wave-damping gutters shall be in operation on all four sides of the basin.

Article 3.3: The hall

1. 3.3.1The air temperature shall be no more than 2.0 °C above the water temperature.
2. 3.3.2Relative humidity shall be between 55% and 65%.
3. 3.3.3Background noise shall not exceed 58 dBA with spectators present and 45 dBA during warm-up.
4. 3.3.4Spectators shall remain seated and silent during chukkas. Applause is permitted only during the 60-second interval between chukkas.
5. 3.3.5Ceiling height above the water surface shall be at least 5.0 m to limit acoustic reflection.