Modern plumbing systems use several types of pipes, including PVC, PEX, copper, ABS, cast iron, and galvanized steel. Each type of pipe serves a specific purpose, with plastic pipes commonly used for water supply lines and drainage pipes, while copper pipe and stainless steel pipes are often found in residential plumbing for hot water and cold water applications.
Plumbing pipes come in many different materials, and choosing the right one matters for your home or business. The pipes carrying your potable water are very different from the drainage pipes that move wastewater away. This guide breaks down the most common kinds of pipes in plumbing, what each one is best for, and what you need to know about pipes in older homes versus new construction.
What Are the Most Common Kinds of Pipes in Plumbing?
The most common plumbing pipes fall into two main groups: plastic pipes and metal pipes. Plastic piping has become the dominant choice for residential plumbing across the United States, with PEX piping leading new construction installations since the early 2000s.
Here are the seven types of pipes you will find most often:
- PVC pipe (polyvinyl chloride)
- PEX pipe (cross-linked polyethylene)
- ABS pipe (acrylonitrile butadiene styrene)
- Copper pipe (rigid copper and flexible)
- Galvanized steel pipe
- Cast iron pipe
- Stainless steel pipes
Each one has strengths and weaknesses depending on whether it handles hot water, cold water, drain line flow, or vent pipes.
What Are the Different Plastic Pipes Used in Plumbing?
Plastic piping makes up the majority of pipes in new construction today. The three main plastic pipe types are PVC, PEX, and ABS, and each fits a different role in your plumbing system.
PVC Pipe (Polyvinyl Chloride)
PVC pipe is a rigid white plastic pipe that handles cold water supply lines, drain lines, and vent pipes. It is lightweight, affordable, and offers strong corrosion resistance.
- Best for: drainage pipes, irrigation systems, vent pipes, cold water lines
- Lifespan: 50 to 80 years
- Not recommended for: hot water (high temperatures can cause warping)
- Installation note: should not be installed in direct sunlight without a protective coating
PEX Pipe (Cross-Linked Polyethylene)
PEX piping has grown into a popular choice for water supply in residential plumbing. PEX pipe is flexible, easy to install, and works for both hot water and cold water lines.
- Color-coded: red for hot, blue for cold, white for either
- Cold weather performance: holds up better in freezing temperatures than rigid pipes because it can expand slightly
- Connection type: compression fitting hardware or crimp rings
- Lifespan: 40 to 50 years
ABS Pipe (Acrylonitrile Butadiene Styrene)
ABS pipe is a black plastic pipe similar to PVC, but used mainly for drain line and vent pipe applications. It handles impact slightly better than PVC.
- Best for: drainage pipes, sewer lines
- Installation note: cannot be used in direct sunlight (UV light breaks it down over time)
- Commonly found in: older homes built between the 1970s and 1990s
What Metal Pipes Are Used in Plumbing Systems?
Metal pipes have been part of plumbing for over a century. Plastic piping has taken over many roles, but metal pipes still play important parts in modern systems and remain very common in older homes built with different materials than what we use today.
Copper Pipe
Copper pipe is one of the most trusted plumbing materials. Rigid copper handles both hot water and cold water, and it resists bacterial growth naturally. According to the Copper Development Association, copper plumbing pipes can last 70 to 80 years when installed correctly.
- Best for: water supply lines, hot water lines
- Corrosion resistance: strong
- Cost: higher than plastic pipe options
- Connection type: compression fitting or soldered joints
Galvanized Steel Pipe
Steel pipe coated with zinc was the standard water pipe in homes built before the 1960s. You will still find galvanized steel in many older homes today, though it is rarely used in new construction.
- Lifespan: 40 to 50 years
- Common issues: prone to rust and mineral buildup over time
- Performance note: can restrict water flow as it ages
Cast Iron Pipe
Cast iron is the heavyweight of drainage pipes. You will find this iron pipe in older homes as the main stack and sewer line. It is quiet, strong, and can last 75 to 100 years.
- Best for: main drain lines, vent pipes in multi-story buildings
- Installation note: heavy and harder to install than plastic piping
- Common issues: can rust and crack at joints over decades of use
Stainless Steel Pipes
Stainless steel pipes cost more than copper or plastic, so they are reserved for specific situations. They are common in coastal areas where saltwater air corrodes other metal pipes quickly.
- Best for: high-end residential plumbing, commercial buildings, marine environments
- Corrosion resistance: excellent
- Cost: most expensive option
What Pipes Are Used in Older Homes?
If you own an older home, the type of pipe in your walls may be very different from what you would see in new construction. Knowing what you have helps you plan repairs and replacements.
| Pipe Material | Era of Use | Common Issues |
| Lead pipe | Pre-1930s | Lead leaching into potable water (health risk) |
| Galvanized steel | 1930s to 1960s | Rust, low water flow, burst pipe risk |
| Cast iron | Pre-1980s | Cracking at joints, root intrusion |
| Clay pipes | Pre-1950s | Root intrusion, cracking, collapse |
| Copper pipe | 1960s to present | Pinhole leaks in some water conditions |
Lead pipe is the most concerning of these. The EPA has set limits on lead in drinking water, and any home with a lead pipe service line should consider replacement. Clay pipes were once the standard for sewer lines but have been replaced in nearly all new installations.
How Do You Choose the Right Type of Pipe for Your Plumbing Needs?
Choosing the right pipe depends on the job. A licensed plumber will look at temperature, pressure, location, and local codes before making a recommendation. Here is a quick reference based on common plumbing needs:
For Water Supply Lines
- First choice: PEX piping (flexible, freeze-resistant, affordable)
- Second choice: Copper pipe (long lifespan, trusted)
- Avoid: Galvanized steel or lead pipe
For Drain Lines and Sewer Lines
- First choice: PVC pipe (affordable, resists corrosion)
- Second choice: ABS pipe (similar to PVC, slightly more flexible)
- Heavy-duty option: Cast iron (quieter, long-lasting)
For Hot Water Lines
- First choice: Copper pipe or PEX pipe rated for high temperatures
- Avoid: Standard PVC (it can warp)
For Outdoor and Irrigation Systems
- First choice: PVC pipe (when buried or shaded)
- Avoid: Any pipe left in direct sunlight without UV protection
Comparison Table: Common Plumbing Pipes at a Glance
| Pipe Type | Material | Best Use | Lifespan | Hot Water Safe |
| PEX | Cross-linked polyethylene | Water supply | 40 to 50 years | Yes |
| PVC | Polyvinyl chloride | Drain, cold supply, vent | 50 to 80 years | No |
| ABS | Acrylonitrile butadiene styrene | Drain, vent | 50 to 80 years | No |
| Copper | Rigid copper | Water supply | 70 to 80 years | Yes |
| Cast Iron | Iron pipe | Main drain, sewer | 75 to 100 years | Not applicable |
| Galvanized Steel | Steel pipe with zinc | Older water supply | 40 to 50 years | Yes (older homes) |
| Stainless Steel | Stainless alloy | Specialty water supply | 70+ years | Yes |
When Should You Call a Professional Plumber?
A burst pipe, slow drain, or strange noise in your plumbing can mean a serious problem. Some pipe issues you can spot yourself, but most repairs require a professional plumber. Call a licensed plumber if you notice:
- Discolored water (often a sign of corroded galvanized steel or iron pipe)
- A burst pipe or visible leaks
- Drops in water pressure across multiple fixtures
- Repeated clogs in your drainage pipes
- You have an older home and want to know what pipes are behind your walls
Expert plumbers can run a video inspection to check the condition of your pipes without tearing into walls or digging up your yard. This saves time and money compared to guessing.
Taking Care of Your Home’s Plumbing
The kinds of pipes in your plumbing system shape how it performs and how long it lasts. From PEX piping in new construction to cast iron drain lines in older homes, each pipe plays a role in moving water in and out of your property. Knowing what you have and what to look for helps you plan ahead and avoid major repairs.
If you have questions about the pipes in your home, or if you have a clog or leak that needs attention, John’s Sewer and Drain Cleaning is here to help. Our experienced technicians have an average of 10 to 15 years of experience, and we offer 24/7 emergency service across the Boston area. Contact us today to schedule an inspection or get help with your plumbing needs.