Which of the following pipework materials is approved for internal cold water installations?

• A. Plastic
• B. Lead
• C. Copper
• D. Galvanized steel

Answer: (C)

Copper is approved for internal cold water installations because it is safe for potable water, durable, and easy to join with reliable fittings. It won’t leach harmful substances into the water, and it forms a protective surface that resists corrosion from typical cold-water supplies. Copper piping can handle the normal pressures and temperatures of cold-water systems, and joints made by soldering or compression fittings are well-proven and long-lasting. This combination of safety, reliability, and compatibility with standard fittings makes copper the preferred choice for internal cold-water piping. Lead is not acceptable due to health risks, galvanised steel can corrode and cause mineral buildup, and while plastic options are common in modern systems, copper remains the standard answer in many contexts for internal cold-water installations.