There are a number of reasons to explain the shortages: apart from abnormal weather associated with El Nino, reservoirs have been poorly maintained for many years and are heavily silted up, reducing their ability to retain water; other water stores and channels, such as retaining ponds in the Taipei and Taoyuan area, have disappeared; and an inappropriately high percentage of water (50 %) has been going to agriculture.
至於各地缺水原因，除了聖嬰年天氣反常，久旱不雨；水庫「年久失修」，泥沙淤積嚴重、蓄水功能減低，其他蓄水管道如桃園台地水塘消失，加上未及時調度佔用水量比例高達五成的農業灌溉用水，也是原因。