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What Is The Difference Between L And M Copper Pipe?

Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases.

Copper piping systems are widely used throughout the United States. They are used for water supply, sewage disposal, heating and cooling, and other applications.

Copper piping systems consist of copper tubing or copper pipe. The two types differ in size, shape, material, and application.

L copper pipe has larger diameter, thicker wall thickness, and higher tensile strength than M copper pipe. This makes it suitable for high pressure and temperature applications.

It can be used to deliver large volumes of fluids at a constant rate.

M copper pipe (see also ‘How To Unfreeze Your Pipes’) can handle lower pressures and temperatures than L copper pipe. It is usually smaller in diameter, thinner-walled, and less expensive than L copper pipe.

We take a look at the different types of copper pipes, and what you can use them for.

Should You Use L Or M Copper Pipes?

L copper pipe is ideal for delivering large quantities of fluid at a steady flow rate.

For example, this type of pipe is commonly used to transport a lot of water from one point to another.

Type L copper piping is typically used for water supplies in buildings.

In comparison, type M copper pipes are used in most jurisdictions but they are not accepted everywhere.

This is because they are not as durable and long-lasting as L copper piping.

Professional plumbers usually use M copper pipes for heating supplies, such as for underfloor heating. Type M copper piping is also much cheaper than L pipes.

Due to their thickness, L copper pipes contain more copper and therefore are more expensive.

However, if you need to install a new plumbing system, then you should consider using L copper pipes instead of M copper pipes.

The main reason why you would want to use L copper pipes is that they have better corrosion (see also ‘Copper Corrosion: Everything You Need to Know’) resistance.

Another advantage of using L copper piping is that it is easier to clean because it is bigger.

Why Do Some Jurisdictions Require Type L Copper Pipes?

If you live in an area where L copper piping is required by law, then you will probably find yourself having to buy L copper pipes.

These laws vary from state to state. However, in some states or jurisdictions, only L copper piping is allowed in certain buildings.

For example, in California, L copper piping must be installed in all residential homes and commercial establishments.

The reason for this is mainly water pressure. Some water sources require a much higher water pressure, and only the thicker L pipes can withstand this water pressure.

It’s best to speak to a professional plumber before buying and installing any pipes.

However, you will need to ensure that you meet the requirements for your building project.

If you installed the wrong type of copper pipes, then you will need to remove and replace them with the correct ones.

This can cost a lot of time and money, so it is important to check upfront what type of piping your home requires.

It is important to note that there are no specific requirements when it comes to installing M copper piping.

Types Of Copper Pipes

There are typically four different types of copper pipes. Each one can be identified by the different coloring on the outside of the pipe.

K Copper Pipes

K copper pipes are the only copper piping that you can use underground. It is very popular for its durability and longevity.

This makes it ideal for any water supply lines that run underground from main water sources to your household plumbing.

They are made out of pure copper and are relatively thick-walled. This makes them suitable for high-pressure applications.

K copper can be identified by a green color on the outside.

DMV Copper Pipes

DMV copper pipes are an old copper pipe standard and they are usually found only in old homes. The DMV stands for drain, waste, and vent.

This indicates that this type of pipe is only allowed to be used in drain and vent supply lines. This means DMV pipes cannot be used for water.

These drainage pipes aren’t used anywhere in new homes, and they are not usually sold in stores.

For this reason, they don’t have a pressure rating.

L Copper Pipes

L copper pipes are one of the most common types of copper piping. These pipes are used for supplying large amounts of water.

You can identify type L copper pipes with a blue color on the outside.

M Copper Pipes

M copper pipes are the smallest in size. They are often used in smaller systems such as faucets and showerheads.

They are also typically used in heating systems thanks to their smaller size.

The advantage of M copper pipes is that they have a dual function. They can be used for a small amount of water supply and heating.

If you use type M copper pipes for water (see also ‘What Causes High Suction Pressure?‘), then it is important to notice that this type of copper pipe is not suitable for large amounts of water.

It has only a thinner wall and will therefore not withstand high water pressures.

You can identify M copper piping with the red color on the outside.

How Is Water Pressure Related To The Thickness Of The Pipe?

How Is Water Pressure Related To The Thickness Of The Pipe?

When you install pipes, it is important to consider the water pressure.

Water pressure is measured in pounds per square inch (psi).

When you buy copper pipes, you need to look at the psi rating to ensure that the pipe can withstand your local water pressure.

A copper pipe with a higher psi rating is more durable than one with a lower psi rating.

Copper pipes are stress-tested in a lab to check how they withstand water pressure. This is how pressure ratings are confirmed.

In addition, the different types of copper pipes also have different wall thicknesses and diameters.

However, a big pipe can also have a thinner wall, which means it would not withstand as much water pressure.

As a rule of thumb, your pipe should be thicker to withstand the higher pressure of water in some areas.

Additionally, piping with thicker walls can also last much longer than thinner walled pipes.

Is Type L Pipe Thicker Than M?

Type L copper pipe is considered thicker than type M copper pipe. This is one of the greatest differences between these two types of copper pipes.

You can find L and M copper pipes with a diameter of 0.5 inches and 0.75 inches. 

The thickness of M copper pipes (see also ‘How To Measure Copper Pipe in No Time‘) is typically 0.032 inches thick. In contrast, L-type copper pipes are typically 0.045 inches thick.

This seems like a small difference on the surface. However, L copper pipes typically last much longer, and they will be able to withstand higher water pressures.

In addition, this also leads to less wear and tear on the pipe, which will also make your pipe last longer.

However, other factors determine whether or not a thick or thinner pipe is suitable for your home.

For example, if you want to know what kind of copper pipe is best suited for your home, you may want to consider the location where the pipe will be installed.

This is because the water pressure in an area varies from place to place.

Therefore, you need to make sure that the pipe you choose can handle the water pressure in your area.

What’s The Price Difference Between L And M Copper Pipes?

L and M copper pipes are not only different in their size and thickness, but they also vary greatly in price.

Due to its slightly greater thickness and durability, type L copper piping is much more expensive than M copper pipes.

This large price difference often means that type M pipes are used wherever possible.

However, professional plumbing experts usually recommend using type L pipes.

They last for longer than M pipes, meaning that they do not need to be replaced as often.

What’s The Lifespan Of A Copper Pipe?

Generally, copper piping can last for as long as 80 years.

However, this depends on many different factors, such as the state of your home and the water pressure in your area.

The higher your water pressure, the more your copper piping system will wear down.

Therefore, if you live in a high-pressure area, you should always keep an eye on your copper piping.


Copper pipes are very popular among homeowners. They are easy to install, and they generally last for many years.

However, you should always remember to take care when installing copper pipes. Make sure that you follow all safety precautions before doing any work.

Frequently Asked Questions

Are Copper Pipes Better Than Plastic Pipes?

Yes, copper pipes have proven traditionally to be better than plastic pipes. They are stronger, more durable, and easier to install.

Although plastic pipes are cheaper, they are also weaker than copper pipes.

If you live in an area with high water pressure, then you might prefer copper pipes over plastic pipes.

How Do You Know Which Size Of Copper Pipe To Buy?

If you are looking to buy copper pipes, you’ll first need to decide what diameter you need. You will also need to check the water pressure in your home.

This will impact what wall thickness your copper pipe needs to be.

Is Copper Plumbing Bad?

No, copper plumbing isn’t bad. It withstands corrosion much better than other piping materials.

Copper plumbing has been around for hundreds of years. However, many people believe that it is bad for the environment. This is simply untrue.

There are many benefits to using copper plumbing, such as its durability and ability to withstand higher water pressures.

author avatar
Anthony Barnes
Anthony Barnes is the founder of Water Heater Hub and a second-generation plumber by profession. Before developing Water Heater Hub, Anthony Barnes was a full-time plumber, and he has undertaken a wide variety of projects over the decades. As a second-generation plumber, it was easy for Anthony to get used to the technicalities of all from a tender age


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