For a residential project, which type of plumbing pipe is most often utilized for hot water supply?

Copper is the most commonly used plumbing pipe for hot water supply in residential projects due to its excellent thermal conductivity and resistance to corrosion. Copper pipes can withstand high temperatures and pressures, making them ideal for hot water systems. They are also durable and have a long lifespan, which is essential for plumbing applications. Additionally, copper has inherent antimicrobial properties, contributing to the safety and quality of the water supply.

While other materials like PVC and polypropylene have their uses, they are not typically recommended for hot water supply. PVC cannot handle the high temperatures of hot water and may warp or become brittle when exposed to heat. Polypropylene is more flexible and can handle some heat but is generally used for tasks that don't involve high-pressure hot water. Ductile iron is primarily used for water transmission in larger municipal systems, rather than residential plumbing. Hence, copper remains the preferred choice for residential hot water supply lines.