Home Postcodes by state SA 5155 Postcode 5155 5155 is the postcode for 2 localities in SA: Bridgewater and Mount George. Localities with postcode 5155BridgewaterSAMount GeorgeSA Postcode 5155 State or territory South Australia (SA) Localities 2 Council area Adelaide Hills Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 5154 · Postcode 5156