Home Postcode finder WA Grass Patch Grass Patch postcode WA Grass Patch is a locality in Western Australia covered by postcode 6446. Postcode 6446 State or territory Western Australia (WA) Region Wa Subs 1 G Flds Add a free Grass Patch business listing More business listings in Grass Patch Businesses in Grass PatchGrass Patch Primary SchoolFreeman St · 08 90757042 Common questionsWhat is the postcode for Grass Patch?Grass Patch, WA has the postcode 6446.What state is Grass Patch in?Grass Patch is in Western Australia (WA).Does postcode 6446 cover more than one suburb?No. Postcode 6446 covers Grass Patch only, which is unusual - most Australian postcodes cover several localities. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.