The camphor industry suffered competition from synthetic products while the Tamsui River suffered heavy silt build up which eventually curtailed sailboat trade. The recovery of Taiwan in 1945 did little to turn around Sanhsia's fortunes, and the city began to slip into quiet obscurity.
茶農和茶商在此以最原始的交易方法買賣茶菁。有木、插角、九鬮一帶，都仍留存著這種習俗，而以茶廠林立的九鬮茶市，歷史最久，經常吸引許多好奇的觀光客到此參觀。