Water budgeting experiments were conducted in three portable FRP carp hatchery units installed in three different places of Odisha State, India. Induced breeding programmes were conducted for spawn production for seven times in these FRP hatcheries taking rohu, Labeo rohita as the test species. Water requirement for one complete cycle of FRP carp hatchery operation was calculated to be 105 - 136.3 m3, when spawn production ranged between 0.7 and 1.4 million per operation in field condition. It was estimated that the water requirement per 0.1 million spawn production ranged between 8.86 - 15.01 m3. It was concluded that the water requirement for FRP carp hatchery operation was comparatively more when less quantity of carp spawn produced and was less when more spawn produced.