Home Postcodes by state WA 6228 Postcode 6228 6228 is the postcode for Waterloo, WA. Localities with postcode 6228WaterlooWA Postcode 6228 State or territory Western Australia (WA) Localities 1 Council area Dardanup Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6227 · Postcode 6229