Oman Plumbing Materials - Materials. Water systems of ancient times relied on gravity for the supply of water, using pipes or channels usually made of clay, lead, bamboo, wood, or stone. ... Today, most plumbing supply pipe is made out of steel, copper, and plastic; most waste (also known as "soil") out of steel, copper, plastic, and cast iron. Are you looking in Oman plumbing materials manufacturers, wholesalers, suppliers and retailers. Call below business card details.