Very important factor for crop cultivation are water, nutrient and temperature. However, the essential factor for crop cultivation is water management. Water management is the most important and difficult problems in crop cultivation. The water saving irrigation manual can be used with easy to the farmer and who want automatic irrigation without soil sampling and any kinds of sensors measuring soil water status. The water requirement of red pepper cultivated in plastic film house is different according to soil texture, area as well as climate condition and growth stage. And, the measurement of potential evapo-transpiration (PET) and crop coefficient (Kc) to decide optimum irrigation schedule is very difficult. Results : The average PET during 30years of northern region of korea for the red pepper cultivation was a 2.31 mm day-1. The water saving irrigation manual as water saving is possible, those irrigation interval and amount of irrigation according to growing season and soil texture, are developed using the lysimeter experiments carried out by the RDA for 11years about potential evapo-transpiration, Kc for the northern region of korea.