A drain assembly includes a drain head, which includes a flange and a cylindrical stem, with the flange extending outwardly from the cylindrical stem. The assembly also includes an adapter. The adapter is configured to engage the cylindrical stem of the drain head to adjustably support the drain head on the adapter and has a support flange, the support flange having a top surface. The assembly further includes a clip having a top end and a bottom end. The top end of the clip is connected to an underside of the flange of the drain head and the bottom end is configured to engage the top surface of the support flange of the adapter to permit downward adjustment of the drain head with respect to the adapter and prohibit upward adjustment of the drain head with respect to the adapter.