When it comes to kitchen and bathroom plumbing, commonly recommended materials include copper, PEX (cross-linked polyethylene), and PVC (polyvinyl chloride). Copper is durable and resistant to corrosion. PEX is flexible, making installation easier, while PVC is cost-effective for drainage systems. The choice depends on budget, function, and local building codes. Consulting a professional plumber can help determine the best materials for your specific plumbing needs.