Crop water requirements vary with growth stages and environment. The Penman-Monteith method is used to estimate potential evapotranspiration. By multiplying this with a crop coefficient, the water needs of different crops can be determined. Changes in weather have led to a decrease in reference evapotranspiration. The study found that evapotranspiration varies by location, day, month, and season. Corrected crop coefficients were used for different stages of crop growth. The study estimated water requirements for 16 crops in Gujarat, India, including horticultural crops.