What is the main material used for sewer pipes?

The main material used for sewer pipes is ABS plastic. This material is favored for its lightweight nature, ease of installation, and resistance to corrosion, which makes it particularly suitable for waste and vent applications. ABS (Acrylonitrile Butadiene Styrene) is also durable and can withstand the harsh chemicals typically found in sewage, contributing to its long lifespan in plumbing systems.

While copper and cast iron have their applications in plumbing, they are not the primary materials used for sewer pipes. Copper is often used for water supply lines due to its resistance to corrosion and bacteriostat properties, but it is more expensive and less common in sewage applications. Cast iron, while historically used for sewer systems due to its strength and durability, is largely being replaced by plastic materials like ABS due to the latter's weight advantage and cost-effectiveness.

Thus, ABS plastic stands out as the most commonly utilized material in modern sewer piping systems, making it the correct choice.