Home Postcodes by state SA 5090 Postcode 5090 5090 is the postcode for Hope Valley, SA. Localities with postcode 5090Hope ValleySA Postcode 5090 State or territory South Australia (SA) Localities 1 Council area Tea Tree Gully Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 5089 · Postcode 5091