The water pollutant balance was analogized to know treatment tendency according to the treatment time. The total influent amount of hydroponic wastewater was 0.26~0.34 m³ day^-1 on the average for two years, the amount of hydroponic wastewater evapotranspiration was 15~18% in hydroponic wastewater treatment plant. In the case of COD balance, the inflow was 2.27~2.33 kg year^-1 in hydroponic wastewater treatment plant. 34.4~34.8% of COD in 1^st HF bed was treated. And 45.4~46.8% of COD in 2^nd HF bed was treated. Therefore, the outflow of 0.43~0.46 kg year^-1 in COD was 18.5~20.3% in hydroponic wastewater treatment plant. In the case of T-N balance, the inflow was 8.74~11.67 kg year^-1 in hydroponic wastewater treatment plant. 21.3~24.3% T-N in 1^st HF bed was treated. In 1^st HF bed, 0.27~0.5% of T-N by water plant, 2.49~6.64% of T-N by filter media and 17.2~18.7% of T-N by the others were treated, respectively. And 37.5~37.7% T-N in 2^nd HF bed was treated. In 2^nd HF bed, 0.26~0.49% of T-N by water plant, 5.26~5.60% of T-N by filter media and 31.8~32.5% of T-N by the others were treated, respectively. Therefore, the outflow of 3.33~4.78 kg year^-1 in T-N was 38.2~41% in hydroponic wastewater treatment plant. In the case of T-P balance, the inflow was 1.44~1.71 kg year^-1 in hydroponic wastewater treatment plant. 62.2~63.2% T-P in 1^st HF bed was treated. In 1^st HF bed, 0.97~1.33% of T-P by water plant, 20.1~41.5% of T-P by filter media and 19.3~42.4% of T-P by the others were treated, respectively. 29.9~32.1% T-P in 2^nd HF bed was treated. In 2^nd HF bed, 0.81~1.1% of T-P by water plant, 8.3~30.4% of T-P by filter media and 0.58~20.8% of T-P by the others were treated, respectively. Therefore, the outflow of 0.1 kg year^-1 in T-P was 5.8~6.9% in hydroponic wastewater treatment plant.