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Types of Copper Pipe: Choosing the Right Option for Your Plumbing Needs

Copper piping is a fundamental component in both residential and commercial plumbing, renowned for its durability and reliability. With various types available, each suited for certain applications, understanding the distinctions between them is crucial for making informed decisions in plumbing projects.

The most common types found in plumbing systems are Type K, Type L, Type M, and DWV (drain, waste, and vent). Each type is categorized based on wall thickness, pressure rating, and the specific installation environment.

Copper pipes in the factory

The thicker walls of Type K copper pipe make it the most durable, suitable for high-pressure applications and for use underground or when the pipe must be supported across long spans. Meanwhile, Type L is known for its balance between strength and flexibility, making it a good fit for interior plumbing and heating. Lastly, Type M has thinner walls than Type K and L, which makes it a cost-effective option for low-pressure applications within homes.

In addition to these, DWV copper pipes specialize in non-pressurized systems such as drain, waste, and vent lines, where strength requirements are comparably lower.

Each type has its method of fitting, advantages, areas of use, and factors that are essential to consider to ensure the success and longevity of plumbing structures.

As plumbers and DIY enthusiasts navigate the selection process, awareness of these types provides the foundation for tailored and effective plumbing solutions.

Types of Copper Pipe

In the realm of plumbing and construction, copper pipes are highly sought after for their durability and versatility. There are four common types of copper pipe available, each suited for different applications and requirements.

Type K Copper Pipe

Type K copper pipe boasts the thickest wall of all the copper pipe types. Its robust construction allows for use in underground installations such as water mains and as a dependable option for heavy-duty applications.

Type L Copper Pipe

Type L copper pipe strikes a balance between thickness and flexibility, making it suitable for interior water supply lines. It is a popular choice for residential and commercial settings due to its moderate thickness and versatility.

Type M Copper Pipe

The walls of Type M copper pipe are thinner than Types K and L, rendering it less expensive and more commonly used for indoor plumbing applications where pressure is relatively low.

Type DWV Copper Pipe

This type, known as DWV (drain, waste, vent), presents the thinnest walls and is specifically designed for non-pressure systems like sewer and vent lines in a home's plumbing system.

Applications of Copper Pipes

Copper pipes in warehouse

Copper pipes are integral components in various systems due to their durability, corrosion resistance, and thermal conductivity. These characteristics make them suitable for a broad range of applications across different industries.

Plumbing Systems

In plumbing systems, copper pipes are frequently used for water supply lines due to their longevity and the ability to withstand high water pressure.

For this application, Type L and Type M copper pipes are commonly used, with the former being thicker and thus more commonly used in underground service lines, where durability is paramount.

HVAC Systems

For HVAC systems, copper pipes are essential in distributing warmth and coolness efficiently.

The high thermal conductivity of copper makes it an excellent choice for refrigerant lines in air conditioning units and for hot water radiators in heating systems.

Medical Gas Systems

Copper pipes are also utilized in medical gas systems, delivering gases like oxygen and nitrous oxide. The non-permeable nature of copper ensures that the medical gases are not contaminated, which is critical in healthcare settings.

Industrial Uses

In industrial uses, copper pipes transport various liquids and gases, including natural gas and oil.

They are also employed in fire suppression systems, owing to their ability to withstand high temperatures, and in radiant heating systems, given their efficient heat transfer properties.

Copper Pipe Fittings

Many thick copper pipes

Copper pipe fittings are essential components used to connect different sections of copper pipe in a plumbing system. They facilitate changes in direction, allow extensions, and provide the capability to connect different sizes or types of pipes.


Elbows are fittings that allow copper piping to turn corners or change directions. A typical elbow provides a 90-degree angle, but 45-degree elbows are also available for less sharp turns.

They come in various sizes to match the diameter of the pipes they're connecting.


Couplings are designed to connect two straight sections of copper pipe of the same diameter. They come in two types:

Slip couplings slide over the pipe, while compression couplings use a ring that's tightened around the pipes to secure them in place.


Tees are three-way fittings used to either combine two inflow pipes into one or split one outflow pipe into two paths. They are identified by their T-shaped appearance and generally have slip ends for easy installation.

The main run of the tee is in line with the connected pipe, while the branch provides a 90-degree outlet.


Adapters function to transition between different types or sizes of pipes, such as from copper to PVC or steel. They come in various forms, such as male or female adapters, depending on whether they are designed to fit inside a fitting or onto an external thread.

Installation and Handling

Twisted new copper tubes on a black background

When installing copper pipes, one must consider proper techniques for cutting and joining, as well as the need for support structures and allowances for thermal expansion and contraction.

Cutting and Joining

Copper pipes can be cut using a tubing cutter or fine-toothed saw. After cutting, one should rename the inside to remove any burrs to prevent turbulent flow and potential wear and tear.

Joints can be made using soldering for rigid pipes or compression fittings for flexible types.

Soldered joints require a clean surface and the application of flux before heating and applying the solder.

Support and Hangers

To prevent sagging or movement, copper pipes should be properly supported using hangers and straps.

The choice of support depends on the weight and size of the pipe as well as the distances between supports:

     ●For horizontal runs of Type K, L, or M copper tubes, supports should be spaced approximately every 6 feet.

     ●Vertical pipes should have support at each floor level they pass through.

Expansion and Contraction

Copper pipes expand and contract with temperature changes. To accommodate this, installers should:

     ●Use sliding brackets for supports or loops in the pipework at larger intervals to allow movement.

     ●Maintain a minimum of 1.5 times the pipe diameter as a gap between the pipe and surrounding materials to prevent damage from thermal expansion.


Copper pipe remains one of the most durable, reliable options for residential and commercial plumbing systems. When choosing copper, it is important to understand the differences between the main types - K, L, M, and DWV. 

Selecting the right variety of copper pipes for each application in your plumbing can maximize performance longevity. Consult with professional plumbers to determine what types of copper pipe are recommended for any new installation repairs. 

And remember - when cared for, piping can last for many decades, a smart long-term investment in your home or building's plumbing.