Guide to Pipe Materials in Hong Kong Buildings
The pipes hidden inside your walls deliver clean water and carry waste away. Hong Kong's building stock spans over a century, and plumbing materials have evolved dramatically. Understanding what pipes your building has helps you anticipate problems, budget for replacements, and make better renovation decisions.
Galvanised Iron (GI) Pipes
GI pipes were the standard for fresh water supply from the post-war period through the 1980s — steel pipes coated with zinc to resist corrosion. Found in most tong lau, pre-1990s public housing, and private blocks of that era.
- Pros: Strong, rigid, widely understood by HK plumbers with fittings readily available.
- Cons: Once the zinc coating fails, steel corrodes rapidly. Internal rust reduces flow, discolours water, and can contaminate drinking water with iron. Threaded connections leak as they corrode.
- Lifespan: 20 to 40 years. Many in Hong Kong are well past this.
- Replacement cost: HK$15,000 to HK$35,000 for a typical 400–600 sq ft flat, including wall repair.
If your GI pipes are over 25 years old, replacement is a priority. The Water Supplies Department actively encourages this, and some districts offer subsidies through the Urban Renewal Authority.
Copper Pipes
Used in Hong Kong since the 1970s, particularly in higher-end developments. Became more common in the 1990s as an upgrade from GI.
- Pros: Excellent corrosion resistance with a protective patina that improves with age. Does not contaminate water. Naturally antibacterial. Handles high pressure and hot water well.
- Cons: Significantly more expensive than plastic — both materials and skilled labour for soldered joints. Can develop pinhole corrosion with aggressive water chemistry. Subject to global copper price fluctuations.
- Lifespan: 50 to 70 years or more. Many 1970s installations still function well.
- Replacement cost: HK$25,000 to HK$50,000 for a typical flat.
PPR (Polypropylene Random Copolymer) Pipes
PPR has become the material of choice for new construction and renovations in Hong Kong. These green or white plastic pipes are joined by heat fusion welding, creating seamless connections.
- Pros: Completely corrosion-proof — will never rust or contaminate water. Rated for hot water up to 95°C. Smooth interior maintains consistent flow for decades. Heat-fused joints are stronger than the pipe itself. Most economical quality option.
- Cons: Cannot tolerate prolonged UV exposure, so external runs need protection. Less impact-resistant than metal. Requires a specialised fusion tool, though most HK plumbers now have one.
- Lifespan: 50 years or more under normal conditions.
- Replacement cost: HK$12,000 to HK$28,000 for a typical flat — the most affordable quality option.
PVC (Polyvinyl Chloride) Pipes
PVC is used for drainage and waste water rather than fresh water supply. The white or grey plastic pipes connecting sinks, toilets, and floor drains to the building's drainage stack are typically uPVC.
- Pros: Inexpensive, lightweight, easy to join with solvent cement. Excellent chemical resistance. Smooth interior resists grease buildup. Widely available at building material suppliers across Hong Kong.
- Cons: Not suitable for hot water — softens above 60°C. Becomes brittle with age and sunlight exposure. Joints cannot be disassembled without cutting.
- Lifespan: 25 to 40 years for drainage use.
- Replacement cost: HK$5,000 to HK$15,000 for drainage within a flat.
When Should You Upgrade?
Consider replacement when you notice discoloured water, reduced pressure, visible corrosion, recurring leaks, or when planning a major renovation. Renovating without addressing ageing pipes is a missed opportunity — accessing pipes after new tiles and cabinets are installed is far more expensive. For fresh water, most Hong Kong plumbers now recommend PPR for value or copper for premium longevity. For drainage, uPVC remains the standard. Whichever material you choose, ensure your plumber is experienced with that system and uses reputable fittings.