The area administered by the office is located in the northwest of Taiwan and spans Taipei, Taoyuan and Hsinchu county, covering 12 townships and cities including Yingge, Bade, Daxi, Longtan, Guanyin, Zhongli, Xinwu, Yangmei, Hukou and Xinfeng. The elevation is 100-240 meters above sea level, and the slope gradient is about 1:80 to 1:120, from southeast to northwest and forms a fan-shaped alluvial hilly area. It extends east to Yingge District, New Taipei City and west to Fengshan River, Hsinchu County. There are hills in the south in the form of the Taoyuan tableland plateau which borders the area administered by the Taoyuan Irrigation Area Management Office. Within the irrigation area Nankan River, Xinjie River, Laojie River, Dajue River, Shezi River and other rivers form a natural drainage system. The Longtan High-Low-Range Irrigation District was removed from office jurisdiction in July 1980 due to the successive establishment of industrial zones within the irrigation area and development of public amenities such as roads, which caused the irrigated area to decrease overtime.
Average annual rainfall in the irrigation area is about 2,000 mm and is abundant. The average annual temperature is 21.8 degrees Celsius, making it a subtropical island climate suitable for double cropped fields. Within the irrigation area, clay loam accounts for 60 percent of land, clay and sandy loam for 20 percent each and the land is fertile.
(1) Irrigation water sources: Shimen Reservoir is the main source of irrigation water in the area under the jurisdiction of the office, followed by reserve ponds (435) for storage and irrigation, weirs (140) for return irrigation, and deep wells (7) to pump irrigation water from groundwater sources (in hyper-drought periods).
(2) Irrigation channels: The main irrigation channels in the area under the jurisdiction of the office are the Shimen Main Canal, as well as the Yuanshu Lateral Canal, Shezi Lateral Canal, Dongshi Lateral Canal, Zhongli Lateral Canal, Puding Lateral Canal, Guoling Lateral Canal, Nanshi Lateral Canal and Pingzhen Lateral Canal, Shanxi Lateral Canal, Shanlu Lateral Canal, Huanding Lateral Canal, Gaoshan Lateral Canal, Changgangling Lateral Canal, Raoling Lateral Canal and Hukou Lateral Canal etc.
The office currently administers an irrigation area of 12,085 hectares, all of which is double cropped rice with no other hybrid crops. The rice seedling cultivation period for the first crop is 29 days, with 110-120 days for field irrigation; with a 15 day rice seedling cultivation period for the second crop and 105-11 days for field irrigation: Field irrigation rate (ha/cms) for various stages: seedling field preparation: 48, water irrigation: 576, field preparation: 216 and growing field: 910-1270.