Home Postcodes by state WA 6175 Postcode 6175 6175 is the postcode for Singleton, WA. Localities with postcode 6175SingletonWA Postcode 6175 State or territory Western Australia (WA) Localities 1 Council area Rockingham Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6174 · Postcode 6176