Sagging Sewage System Lines-- Dust improvements can make your drain line to sag. When this happens, the area which has sunk accumulates paper and also waste resulting in a blockage.?? ?????? ??? ?????????????, ???????????? ????? ??????????? ??? ??? ?? ???? ????????? ???, ???? ??? ??????? ???? ????? ????????? ?????? .?? ?????? ???????? ??????? ??? ?