The Western Water Catchment is a planning area located in the West Region of Singapore. The planning area borders Tuas and Pioneer to its south, Sungei Kadut, Choa Chu Kang and Tengah to its east, Jurong West to its southeast, Lim Chu Kang to its north and the Straits of Johor to its west. It is the largest planning area by land area, covering nearly a tenth of Singapore Island. It is also one of the two main water catchments in Singapore, the other being Central Water Catchment.