Home Postcodes by state WA 6103 Postcode 6103 6103 is the postcode for Rivervale, WA. Localities with postcode 6103RivervaleWA Postcode 6103 State or territory Western Australia (WA) Localities 1 Council area Belmont Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6102 · Postcode 6104