In spite of the area's richness, the population of Erhshui has dwindled over the years to its present level of about 22,000. Factors contributing to this decline have been a drift of workers to the cities, because of the limited land area and number of factories in the Erhshui area, and a falling birth rate as family planning techniques have been implemented.
二水鄉人口約兩萬兩千餘人，由於可耕地面積不大，工廠又少，年輕人到外地謀生的很多，形成人口外流的現象，加上當地衛生機關推行家庭計畫頗有績效，現在全鄉的人口比十年前反而少了幾百人。