Clay Pipes – Made of clay and water, clay was the material of choice from the 1880s to the 1900s. They were durable and resistant to corrosion but were heavy, making them hard to transport.
Failure: Clay pipes are very prone to invading plant and tree roots. The pipe joints can leak if a blockage causes pressure to build up, thus collapsing the pipe. Clay breaks into big pieces, so once it breaks, soil pours in, which results in constant blockages and potential backups(a sewer failure). Plant roots work their way into the joints and cling to the outer surface of the pipe. In some soils, the pipe can shift and sag, come apart, or crumble.
Cast Iron Pipes – Cast iron pipes have been used since the early 1800s for water distribution. Quality cast iron pipes can last 75-100 years and most homes built before the 1970s are equipped with them.
Failure: Cast iron, like all metal, rusts when exposed to water and oxygen. So with sewer pipes, those variables are unavoidable without proper maintenance. Shifting soils, tree roots, and especially chemicals like drain cleaner can damage them over time. We have seen failure in as little as 25 years. Coastal regions with high salt content also accelerate corrosion.