Line Markers Avoid the problems of finding an underground sewer line, water line, electrical line or gas line by using a line marker. Cast Iron line markers can be driven into the ground even below grade level and then easily found with a metal detector. Four options are presently available. Item Number / Description 113 Cast Iron Line Marker "Water" 114 Cast Iron Line Marker "Gas" 115 Cast Iron Line Marker "Sewer" 116 Cast Iron Line Marker "Water" Item # 113-116