Is PEX plumbing good or bad: reasons why and why not

PEX plumbing is a type of plastic pipe for hot and cold water which is typically used in place of copper piping. PEX plumbing has been becoming more popular lately, with advantages such as being less corrosive and cheaper than copper piping.

However, there are some downsides to using PEX, including the possible increased risk of leaks along with potential low water pressure concerns. Let’s discuss these in more detail.


What is PEX?

PEX plumbing was invented in the late 1950s and has been improved a lot over time. PEX stands for cross-linked polyethylene. This is a type of plastic pipe that is used to deliver hot or cold water. It has been popular in Europe and Asia since the 1990s, but it has only recently become a common fixture in North America. Recently it had become a more popular alternative to copper piping. 

A PEX pipe is used to supply water to this sink. It is flexible and easy to work with. Image by PlumbingInstantFix. All rights reserved.

Types of PEX pipes

There are three types of PEX plumbing. The manufacturing method determines the type of pipe.

-PEX-A has shape memory and after you expand it, goes back to its original size. For this reason, it is easier to bend. A lot of plumbers enjoy using this material for this reason. 

-PEX-B is the most common type of PEX. This material needs to be bent carefully (using a bending spring) as it can create weak spots if you don’t do it properly. It is possible that it is needed to use a bigger pipe as the fittings are inside the pipes and this can create flow restrictions.

-PEX-C is less often used in residential plumbing projects so we are not going to discuss this. 

The Advantages of Using PEX Plumbing

PEX plumbing has some advantages over copper piping, including being less corrosive, cheaper, and easier to install. It is also more flexible as you are working with a central point (manifold) that distributes the water over the house. Copper or steel uses a loop and this can make it harder to expand a plumbing system over time. 

PEX is so easy to install that some companies even offer DIY kits that allow normal people to install their own plumbing systems. It is then approved by an inspector so that it can be used.

PEX is also lightweight and this means that it needs fewer supports and can be installed in a lot of locations. 

Copper has gotten a lot more expensive in the past few decades as there was a lot of demand given that it has a lot of applications. It can be up to double the cost of a PEX system.  While the fittings might be more expensive for PEX, there is less need to prepare the material so you are saving on labor costs. 

PEX also has another advantage that is not often discussed. If there is a leak, it can be possible to get the pipe out without having to break the floor or wall. This is done by connecting the old pipe with a new pipe. The new pipe is then pulled in place by getting the old one out. This is not easy to do though and should be left to professionals as it requires a lot of force. It is not always possible to do this but can save on repairs.

Galvanized steel was used a lot in the past but this material is more expensive and quite difficult to install as you need a lot of force to do this. 

The Disadvantages of Using PEX Plumbing: what is wrong with it?

PEX plumbing has some disadvantages that make it not always the best option for your home. These things are bad aspects of using this material.

Potential leaks

One of the most notable disadvantages to PEX plumbing is that it can be more difficult to detect leaks. With copper piping, the water will corrode and leave a stain on the pipes which are easy to see and identify, but with PEX, stains from leaking water may not show up as easily. Manifolds often leak as this is a point where a lot of pipes come together. A small installation mistake can lead to big problems there. 

PEX plumbing is primarily made from polyethylene and polybutylene, which are plastics. As many people know, plastics can be broken by rodents, and this can be a problem if you live in an area with a high rodent population. Rodents nibble on the Pex piping, which can cause leaks. It can be hard to detect as pipes can run behind walls or under the floor. Water damage can be extensive in this way. If you choose to use Pex plumbing, it is important that you minimize your risk of rodents by using materials such as steel wool and sealant around the pipes every few feet. This will reduce any damage caused by rodents.

Reduced water pressure

PEX is often wrongly installed. Plumbers often use the wrong diameter of PEX-B and this leads to low water pressure. The connectors (or fittings) go inside this tube and this restricts the water flow. Plumbers should use wider pipes to compensate for this. These take up more space and are more expensive. A lot of plumbers don’t think about this and it can cause problems. Nothing is more annoying than a shower without a lot of water pressure. This is quite hard to fix and might require the replacement of the pipes. 

Plumbers might not know the right type of PEX

When buying PEX, the installer should ask for a copy of the local code and review it before installing any new system. The local code will identify where PEX may be installed and how it should be installed to ensure compliance with other codes such as plumbing codes or building codes. Some types of PEX might be disallowed in your area. 

Stability of the material

Some older PEX systems might leak chemicals in the water. This can lead to problems down the road. Some people also report that they don’t like the flavor of water that has passed through PEX pipes but this is more a personal preference and newer systems shouldn’t have chemicals in them.

There are different fittings for PEX. Most of them work just fine but don’t use cheap brands.

PEX can’t handle light too well and needs to be stored in a dark area. This is also one of the reasons why PEX tubes are often wrapped with plastic pipes.

Another potential drawback is that certain materials in the PEX pipe may not stand up well against certain chemicals found in water sources, such as chlorine. This can be an issue in certain areas and a filter might be needed for these systems. Luckily, PEX-A is able to resist this so you just have to use the right material for the job. 

It is easier to deform PEX than copper. If someone is standing on a PEX pipe during construction, it can bend or break. Sometimes this can be fixed with a heat gun. Copper is better able to deal with these types of forces. Steel is very strong and won’t bend it people give it a nudge or stand on it. 


Finally, PEX tubing cannot be reused-it’s designed only for one-time use. This makes installing a new system significantly more expensive than if you were to use copper pipe that can often be repurposed by cleaning it. PEX plumbing is difficult to clean if it gets dirty or sticky, unlike copper piping which is easy to clean. 

Copper has a longer track record and it is a proven material. PEX hasn’t been in use for such a long time and we will have to see if more problems emerge and how durable the material is. Both copper and PEX last about 50 years but there are several factors that can affect this. We have to keep in mind that most people renovate their house after 25 years anyway so materials shouldn’t last forever. Granted, being able to recycle a material without too much effort is a big plus. 

To conclude, we can state that while PEX is commonly used nowadays in plumbing pipes, it also has some disadvantages. Some plumbers prefer to use other materials such as PP or copper as they believe that these materials are more durable and qualitative. For most people, PEX pipes will work just fine.

We also have to realize that there are several types of PEX and each has its own unique advantages and disadvantages. PEX-A is often seen as the best option because it is less fragile and doesn’t lead to flow restrictions as easily. 

Water pipes tend to leak at the joints. We have discussed how to fix this here.