Many old houses still have some malleable (cast) iron pipes. Many years ago, 4-inch
drainpipes were used to attach the house drain system to the main sewer line or
septic system. These lines are extremely durable and can last a hundred years
if the ground does not shift. Although the pipe is slowly eroding, most people
have a bigger problem with buildup in the line. The use of chemical drain
cleaner is very harsh on metal pipes and ...