Human urine contains Nitrogen, Phosphorus and Potassium which can be applied as fertilizer for agriculture fields instead of commercially available fertilizer. However, due?to low contents of nutrients in urine, its huge quantity is required to be transported to farmland to meet nutrient demand of crops which increases transportation cost. To?address transportation issue, a new onsite volume reduction system was tested at laboratory scale. Mathematical water transport model was proposed to evaluate performance of the system. Mass transfer coefficient and resistance of water flow through the sheet in the water transport model, were obtained from experiments. The results agreed with simulated data thereby confirming the proposed model. The model was then applied to dry climate of Southern Pakistan having air temperature of 30-40°C and air humidity 20-40% for 80% volume reduction to reduce transportation cost. The findings revealed that the estimated size of the vertical sheet is 2060 ~ 440 cm2, which requires small area for setting up the system at household level.