Ductile iron pipe is a pipe made of ductile cast iron commonly used for potable water transmission and distribution. This type of pipe is a direct development of earlier cast iron pipe, which it has superseded.

Cast iron pipe is a pipe made predominantly from gray cast iron. It was historically used as a pressure pipe for water, gas, and sewage transmission, and as a water drainage pipe during the 17th, 18th, 19th and 20th centuries.