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#6 Copper water pipe vs. plastic pipe

#6 Copper water pipe vs. plastic pipe

As an Aussie plumber, I have been conflicted for a long time on which product is better to use in certain situations.

I have my own personal preferences but during this article I am going to judge each pipe material by a specific set of criteria and at the end of each section I will judge the winner. Hopefully by the end we will have an overall winner!

It is important to note that I have worked for most of my career when plastic pipe has been the dominant pipe work and I do have a preference for plastic pipe before writing this article. Will this article change my mind?

Let’s start with the obvious criteria first:

Pipework characteristics

Plastic water pipe or “pex pipe” is part of the cross linked polyethylene family and is used to supply water services in Australia, the US and Europe.

Pex pipe comes in many different colours which is brilliant if you are a plumber at the installation stage of a home. In certain shires there are additional requirements to install hot water, cold water, tempered water, rain water, and recycled water. It can become very easy to cross connect services and different colours definitely lower the chances of this happening.

The different colours also help you identify both the water type in the pipe and also the brand of pipe (which really helps with future maintenance).

Copper pipe does not come in different colours but it is offered in different forms i.e. annealed, lagged, straight lengths, or rolled. I feel like this variety offered helps copper step above pex in this category.

Winner – Copper ⭐️⭐️⭐️⭐️⭐️

Pipework Flexibility

Plastic pipe usually comes in 50/100m rolls which makes it easy to transport. Two rolls will usually complete a whole job. The flexibility of the pex pipe mean it is great to work with, easy to pull through long pipe runs, and works in tight spaces. Pex pipe is also good when it comes to having to divert around obstacles. Copper on the other hand comes mainly in straight lengths with the coiled annealed copper too expensive to make it a real choice for installation.

Copper certainty keeps its shape better than pex and is also easier to keep neat and straight. However, pex pipes flexibility makes it far faster to install and repair. Copper can be bent at sharp angles but the time cost eliminates this advantage.

Winner – Pex ⭐️⭐️⭐️⭐️⭐️

Heat Resistance

Pex pipe is considered very good when we consider heat loss from hot water travelling through the pipes only gives small losses – making it environmentally friendly and energy efficient.

Copper, on the other hand, has high heat transfer and loss. In colder climates this is a big factor but in sunny Queensland most pipework is run in insulated ceilings space where losses are minimal.

Copper can also be used with much higher water temperatures. Where pex is prohibited, copper is able to withstand the heat associated with the Solar hot water system, storage hot water system connections, and pipework (which is heat and UV exposed to the sun).

Winner – Copper ⭐️⭐️⭐️⭐️⭐️


The pex system is a quiet system and virtually eliminates water hammer and rattling. This is a lot to do with the noise conductivity of pex. It helps that pex is flexible and allows for long radius bends creating less internal friction, and helping reduce the impact of shock waves from coding valves.

When we think of old copper pipework we think of water hammer and rattling pipes and even though standards have improved and technological advances help, copper still cannot complete with the silence of pex.

Winner – Pex ⭐️⭐️⭐️⭐️⭐️


As a rule, pex has a larger out side diameter and small internal diameter, which means copper generally allows for greater water flow for the same size comparison as pex. Even though pex does offer more in sizes through the size range, the major factor still remains that copper is smaller and provides more volume of water.

Winner – Copper ⭐️⭐️⭐️⭐️⭐️

Environmentally Friendly

At the end of the pex system life cycle it will be replaced with another piping system and the old pex thrown away, with only the brass fittings recyclable. On the other hand, copper is 100% recyclable! As a plumber, I continuously trade in copper scraps for cash whereas I throw all pex off-cuts.

Winner – Copper ⭐️⭐️⭐️⭐️⭐️

Impervious Nature of Materials

Copper and pex are both pretty impervious otherwise they wouldn’t be used for water pipe. The reason I bring this criteria into play is because plastic pipe has been known to allow termite chemicals to permeate the water supply. This can be found when it’s installed close to the house boundary in areas where the termite chemical is sprayed.

New rules in the process now is that the last 1-2 meters leading to the house will have to be copper as plastic will be prohibited. Knowing this information, most plumbers should start using this practice anyway! I will pass on the update when it is issued.

Winner – Copper ⭐️⭐️⭐️⭐️⭐️

Pipework Fittings

Pex pipe fittings are dominated by brass fittings, which are heavy and are prone to chemical attack. This being said, I have only ever pulled one corroded fitting out in 11 years and this was due to poor installation!

Pex also comes with a great variety of transition fittings to help the transition from pex to copper, pex to pex and copper to copper!

Pex pipework systems are slowly but surely changing their brass fitting system over to pex fittings too. They are less environmentally friendly but are lighter, cheaper, have less chance of corroding, and are helping make our water more pH friendly.

Pex fittings also come in different forms. For example there are climp type, push fit type, and threaded type – all of which add to the ease of installation.

Copper fittings are basically all copper which helps with the corrosive factor caused by using different metals together. Copper also comes in a variety of types. From crimp to welded to threaded, copper caters for all transition fittings and methods of joining.

Both pex and copper offer great versatility with fittings but ease of installation helps pex win this one.

Winner – Pex ⭐️⭐️⭐️⭐️⭐️

Warranty Periods

The pex piping system has been used in Europe for the best part of 50 years and is still going strong.

Taking this into account, Australian manufacturers offer you a 20-25 year warranty on their pex products, so you can be assured that if the pipework is installed correctly and used as intended, it will comfortably last its warranty period.

Copper manufacturers are so confident that their products are superior that they provide a 50 year warranty on their products. Some wholesalers only pass on a 25 year warranty period, but this is still as long as any pex product I could find.

Winner – Copper ⭐️⭐️⭐️⭐️⭐️


I would say quite easily the biggest reason why most plumbers use pex systems is because of the cheaper cost.

Firstly, pex is a lot cheaper to purchase off the shelf but the big savings come in with installation. For example, where a house used to take two plumbers one day to plumb in the water pipes, it now takes one plumber the same time to do the job, saving huge amounts of time and allowing plumbers more time to take on more work.

Copper has made advances with installation efficiency by the inclusion of the climp style fitting, however these are so expensive that they are only really cost effective when pricing against copper welding.

You could argue that copper has a longer working life but with 50 years of pex use in Europe this factor becomes a little less important.

Winner – Pex ⭐️⭐️⭐️⭐️⭐️

Safety factors

The pex piping system has one massive safety advantage – it doesn’t have the same high electricity conductivity ratings. Electrical technicians can no longer use pex plumbing to earth their wiring. When I go to an old house to repair pipework, I am always weary that the house plumbing may still be carrying electrical current.

From experience, pex crimping tools do present pinch points which hurt if you get caught but nothing major.

Copper pipework definitely presents more installation dangers. Hot welding creates fumes from the welding, and there are potential fire risks to the home or burns to the plumber.

There is a clear winner here.

Winner – Pex ⭐️⭐️⭐️⭐️⭐️

Water Quality

Pex pipework are made up of lots of chemicals and if left for periods of time, have been known leak these chemicals into the water. I have experienced this first hand, but only on one occasion and with a certain brand of pipe I had never used before. To avoid this happening, my advice is to buy a brand which has stood the test of time and this problem shouldn’t occur.

Copper does provide lovely, clean water but also some problems. Scaling over time and poor copper imports are helping detract from the quality that copper has provided in the past. This coupled with the huge technological improvements in pex quality means there is only one winner over the product life time.

Winner – Pex ⭐️⭐️⭐️⭐️⭐️

Pipework sizing

Pex pipework is pretty limited on size variety but this is fine as we usually do not need pex to be any larger than 32mm for commercial or domestic water. The problem is that most suppliers don’t stock pex above 20mm, so anything larger than this needs to be ordered in advance.

Copper on the other hand usually ranges from 6mm to 200mm, sometime larger and is widely available from most stores. You could probably probably walk into a Reece store tomorrow and pick up 100mm copper and fittings off the shelf with no problem.

Winner – Copper ⭐️⭐️⭐️⭐️⭐️

Location uses

Pex piping is mainly used in consealed locations and can be buried under ground or below a concrete slab with proper protection. Pex pipe can not be used in direct sunlight as it is easily damaged by UV rays from the sun.

Copper can also be used in the same places as pex, in addition though copper can be used in direct sun light and is the product of choice for areas where water pipework is exposed due to its nice straight finish and hard shell.

Copper is susceptible to the elements, water driven corrosion and freezing but thermal lagging and good work practices help copper through these weak areas.

Winner – Copper ⭐️⭐️⭐️⭐️⭐️


Copper and pex are both commonly used in water, gas and air installations. Copper is also being used in commercial drainage and fire. The UV resistance and hard shell of copper gives it extra uses in areas where pex is just not viable.

Winner – Copper ⭐️⭐️⭐️⭐️⭐️


When we talk about pex and its associated maintenance issues, a lot of these problems occur from defective installation. For example, the main culprits are pipe rubbing on metal surfaces causing a leak, scratches on pipe at fitting connection causing a leak, and UV damaged pipe. You do hear about rats and mice chewing through pipes but I am yet to see this first hand.

Copper to me is the most problematic when it comes to maintenance. Corrosion from the lime in the concrete and dissimilar metals are a constant source of leaks in the plumbing industry.

Old, hot water units used to have their tanks made from copper however, now nearly all of them have changed to the more reliable stainless steel because the ever decreasing shelf life of the copper tanks.

Winner – Pex ⭐️⭐️⭐️⭐️⭐️


The results are in and the winner is… COPPER with 9 wins! compared to pex systems with 7 wins.

I honestly did not think that copper would win but having spent the time to go through each section I have come to think of copper in a different light.

I will still be using pex for areas which suit pex but I will also be a using copper now in areas I would not have before.


I would take the above considerations into account before choosing a product, starting with cost.

As a plumber I would tell the customer which product I think would be best for the job. If I feel copper is the better product, I will let them know or if I think pex best suits the installation due to high pH levels (acidic side), I will tell them. They are thankful for my advice and expert opinion.


Each product has its merits and can be better suited to plumbing installations in certain conditions. Find the product which suits best. This way the customer gets the best product every time, and not just because of price.


If you need any further assistance, feel free to reach out to Yates Plumbing and Gas. We are local Brisbane plumbers, with a passion for excellence. Our friendly qualified team can help you with all of your plumbing and gas needs.

If you require more information or would like to book our service, please email on or call us on 0437 827 502

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