Selecting the correct material is critical for system longevity. For potable water lines, PEX (Cross-linked Polyethylene) is highly recommended due to its flexibility and scale resistance, while Copper (Type L or M) remains the gold standard for durability and antimicrobial properties. For drainage and waste (DWV), PVC (Polyvinyl Chloride) is the industry standard for its chemical resistance and ease of installation. In high-temperature industrial settings, CPVC or Stainless Steel (304/316 grade) should be prioritized to prevent thermal deformation and corrosion.