Learn the complexities of building plumbing materials as we dive into the pros and cons of different materials like copper, steel, and modern plastic alternatives like PVC, CPVC, and PEX. Deepen your understanding of the materials utilized for water supply and sewage and drainage systems in order to make appropriate choices for your building projects.
Key Insights
- Copper, a traditionally preferred material in plumbing, is known for its durability, corrosion resistance, and heat tolerance. However, it requires soldering at joints, necessitating skilled labor and time, and is relatively expensive compared to plastic alternatives.
- Plastic pipes, particularly PVC, CPVC, and PEX, are increasingly common in both residential and commercial buildings due to their lightweight, corrosion resistance, and cheaper installation costs. PEX is particularly favored for its flexibility and reduced risk of leaks at joints.
- While galvanized steel pipes were once common, they're being phased out due to corrosion and water quality issues. Today, they're typically being replaced by copper or PVC-based systems, which are longer-lasting and safer, especially for potable water applications.
This lesson is a preview from our Construction Management Certification Course Online (includes software & exam). Enroll in this course for detailed lessons, live instructor support, and project-based training.
Plumbing systems rely on different materials depending on whether the piping is carrying clean water into a building or moving wastewater out. In this lesson, we will review the most common plumbing pipe materials used today, compare metal options like copper and steel with modern plastic alternatives such as PVC, CPVC, and PEX, and explain why certain materials are preferred for supply lines versus sewage and drainage.
Water Distribution Piping Materials
Water distribution piping is responsible for carrying potable water through a building for fixtures, appliances, and equipment. The most common options are copper and plastic piping systems. In older buildings, galvanized steel may still be present, although it is increasingly phased out due to corrosion and water quality concerns.
Each material comes with tradeoffs in cost, durability, installation speed, and long-term maintenance.
Copper Piping
Copper has been a standard in plumbing for decades. It is used for both hot and cold water supply and is valued for its reliability in a wide range of conditions.
Learn Construction Management
- Nationally accredited
- Create your own portfolio
- Free student software
- Learn at your convenience
- Authorized Autodesk training center
Why Copper is Still Widely Used
- Durable and long-lasting
- Corrosion resistant
- Heat tolerant, making it suitable for hot water lines
Thickness Grades
Copper piping is available in different thickness grades, often described as thick, medium, and thin. Selection typically depends on factors such as system pressure and application requirements.
Key Tradeoffs
- Skilled labor required: copper joints typically require soldering, which increases labor time and demands experienced installers.
- Higher cost: copper is more expensive than most plastic alternatives, which is why many modern projects choose PEX or CPVC.
Even with these drawbacks, copper remains a preferred material in many systems because of its proven performance.
Plastic Water Supply Pipes: PVC, CPVC, and PEX
Plastic piping is now extremely common in both residential and commercial construction. The three most important plastic pipe types to understand are PVC, CPVC, and PEX. While they are related materials, their use cases differ based on water temperature, flexibility, and installation method.
PVC
PVC, or polyvinyl chloride, is widely used for cold water and drainage. It is not typically used for hot water supply in standard applications.
CPVC
CPVC, or chlorinated PVC, is a modified form of PVC designed to handle hot water. This makes it a common choice for supply systems that need both hot and cold lines but still want a rigid plastic option.
PEX
PEX, or cross-linked polyethylene, is flexible tubing used for both hot and cold water supply. It is a widely favored modern option because it installs quickly and reduces the number of joints required.
- Lightweight
- Corrosion resistant
- Lower installation cost compared to many metal systems
PEX Vs. CPVC: Why Flexibility Changes Installation
PEX and CPVC can serve similar roles as water supply piping, but they behave very differently on site.
PEX
- Flexible and easier to route through complex building paths
- Allows long runs with fewer joints
- Reduces labor time and reduces leak risk by minimizing joints
- Commonly used in modern residential plumbing systems
CPVC
- Rigid, requiring fittings and elbows at turns
- Joints are typically made with solvent cement
- More joints means more connection points that must be installed carefully
Both are approved for potable water systems and are widely used as alternatives to copper. PEX is especially popular because its flexibility makes it faster to install and lowers the number of joint-related failure points.
Galvanized Steel Piping
Galvanized steel is less common in new construction today, but it is still important to understand because many older buildings still contain it. Galvanized steel pipes are steel pipes coated with zinc to resist corrosion.
Why It is Being Phased Out
The zinc coating provides protection initially, but over time it wears away. As the coating degrades, internal corrosion can occur, leading to:
- Rust buildup inside the pipe
- Water discoloration
- Potential water quality concerns due to contamination from corrosion products
Because of these issues, galvanized steel is often replaced with copper or plastic systems in modern upgrades and renovations, especially for potable water supply.
Drainage and Sewage Piping Materials
Drainage systems carry wastewater and sewage out of the building. The most common materials for these systems include PVC, ABS, and cast iron.
PVC for Drainage
PVC is the standard material for many residential and commercial drainage systems because it is:
- Lightweight
- Corrosion resistant
- Easy to cut and join
- Relatively easy to replace if future repairs are needed
ABS for Drainage
ABS is another plastic drainage material, commonly recognized by its black color. It is often used in colder climates because it performs well at lower temperatures.
- Strength: handles cold weather conditions well
- Use case: alternative to PVC depending on regional standards and climate
Cast Iron for Drainage
Cast iron is less common in newer residential construction but still used in certain applications, including main stacks and many commercial buildings.
Cast iron remains valued because it is:
- Extremely durable
- Fire resistant
- Excellent for sound control, helping muffle the noise of flowing water
While cast iron can rust over time, it is often found in drainage systems because it is not carrying potable water, and its durability and acoustic benefits can outweigh the drawbacks in many projects.
Summary: Choosing the Right Material
- Copper is durable and long-lasting but higher cost and labor intensive.
- PEX and CPVC are efficient modern alternatives for water supply, with PEX offering major flexibility and installation speed advantages.
- PVC and ABS are common choices for drainage systems due to ease of installation and corrosion resistance.
- Galvanized steel and cast iron are most often found in older buildings or specific applications where their unique traits still provide value.
What Drives Material Selection
Choosing the right plumbing material depends on several practical factors:
- Cost and labor requirements
- Water temperature and whether the system carries hot or cold water
- Pressure requirements and durability needs
- Ease of maintenance and long-term repair strategy
Understanding these materials and their use cases helps designers and construction professionals select systems that perform reliably, install efficiently, and support the needs of the building over time.
