# PEX or PVC for Water Supplies?



## PlumbingZone (Feb 10, 2016)

Crosslinked polyethylene (PEX) is all the rage in plumbing supplies right now, poised to replace the other popular plastic piping option, polyvinyl chloride (PVC) or chlorinated polyvinyl chloride (CPVC). Will PEX overtake the market share of PVC entirely, rendering the latter obsolete? Only time will tell, but each material has its distinct advantages and disadvantages, making it clear that, for now, PEX and PVC both have their uses and applications. 

*Advantages of PEX *

Introduced in the 1980’s, PEX currently holds 45 percent of the market share of plumbing supplies. This material allows for the installation of both hot and cold, potable and non-potable water lines. 

PEX tubing is exceptionally flexible and requires fewer joints than other plastic plumbing lines. The water-tight connections are weather and humidity-proof and installation doesn’t require glue, torches, gauges or complicated fittings that could fail through use. Instead, the tubing is connected via a crimp fitting or cold-expansion rings. 

*Disadvantages of PEX*

The biggest downside to PEX is the possible economic dent it’ll make in your billings if you charge clients by the hour. While the cost of the material is low, the time it takes to make a connection means you’ll complete the job quicker than with PVC piping.

Be aware that not all types of PEX tubing are impermeable. If you’re installing PEX fixtures to carry potable water (to a sink, for example), make sure you’re using a certified impermeable tubing or there’s a risk of contamination. 

PEX is far more UV susceptible than even PVC. Although short exposure to sunlight during installation is fine, it’s not able to be used in outdoor or above ground applications. Instead, PEX fixtures are limited strictly to indoor or underground outdoor usage. 

*Advantages of PVC*

PVC and CPVC are mainstays in the plumbing world – they hold the majority market share of plastic plumbing fixtures. With more than 60 years of usage in the United States, these materials are the go-to choice for those looking for plastic piping. They’re safe, tested and proven over the course of time. 
Simple PVC can be used in nearly all applications, while CPVC is typically used on only a few. Unlike PEX, PVC and CPVC can be used in outdoor, above-ground applications if a coat of water-based, latex or acrylic paint is used to cover the exterior of the pipes. 

If you bill clients by the hour, PVC and CPVC are more cost-advantageous than PEX, as they require multiple fittings secured by cement. The strength and durability of PVC and CPVC are also greater than PEX – they’re more rigid, meaning more suited to outdoor applications where the piping can be exposed to trauma.

*Disadvantages of PVC *

That rigidity means PVC is less flexible than PEX. Instead of just bending it around a right angle, you must install an elbow. Not only does it mean requiring more materials when installing PVC and CPVC, there are also more connections, which means there’s a greater potential for leaks and failure. 

PVC is not insusceptible to temperature – water pressure changes during temperature fluctuations. PVC and CPVC piping can freeze and crack readily and PVC is also only suitable for cold water applications. For pipes carrying hot water, you MUST install CPVC. 

Although PEX has some very clear advantages over the PVC family of piping, don’t discount PVC and CPVC for many uses. Only PVC and CPVC, when properly coated, can be used outdoors and above ground, whereas PEX cannot. It looks like PEX is here to say, so it’s worthwhile to be familiar with both PEX and PVC plumbing options.


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## rwh (Dec 17, 2014)

This is a pointless post, similar to supply house.com posts on Facebook. I know this site has owners. Those owners must turn a profit to keep the site up. Just put more pop up ads in. Don't post pointless topic starters, all of which have been hashed over many times.


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## rwh (Dec 17, 2014)

BTW, cpvc and PVC is as hack as it comes in residential.


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## indyjim (Apr 29, 2017)

Or they could have brought up how crappy it all is compared to copper. 
The plastic " pipe of the future " has been tried before. Ask any older service plumber about quest, and how much of that crap has he changed out? 


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## WashingtonPlung (Jul 25, 2016)

In washington PVC isn't even allowed for indoor use. You may use CPVC but it's so becomes so brittle over time that I don't know any one who would install it.


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## PLUMBER_BILL (Oct 23, 2009)

indyjim said:


> Or they could have brought up how crappy it all is compared to copper.
> The plastic " pipe of the future " has been tried before. Ask any older service plumber about quest, and how much of that crap has he changed out?
> 
> *I have no idea where they get these "Great Plumbing Photos" My concern in this photo is not the pex, it is the hangers on the PVC ... DWV. The spacing of the hangers and the fact that as shown how many fasters can possibly be in the joists? What hapenes when there is a total blockage? I've seen a few systems installed like this wind up on the floor in broken pieces -- not to mention the mess!*


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## indyjim (Apr 29, 2017)

I will not use j hooks. Either hanger iron or pear hangers. 


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## GAN (Jul 10, 2012)

Oh my goodness. Try to use M copper in part of my area and see how long it lasts before pitting & leaking. PCV, CPVC, PEX type L or K is the only thing that will hold up.

I assume your speaking about water service not DWV. I am seeing more CPVC and some PEX in my area, time will tell. Some 20 years ago the developer I was working with did multiple 4 family adaptable units, all cpvc. The only real issues we had or they still have to date is conversion at tub valves and frost proof sill cocks. As long as it was a cpvc male no problem, cpvc female adapters tended to split. Still holding up.

I can remember when everyone was complaining about ABS or PVC for DWV uses. No unless it is a large commercial project, or a cool down line is needed, a couple of religious uses we all see PVC. I think one of the last holds out was California, heavy union. They wanted to keep the time up for installation and make sure no one else would have an easy time, since yes it takes skill to install cast iron.

Cast iron as well as M copper has it's own issue. The sewer gas will rot the top clean out of a horizontal run, I am sure we have all seen vertical splits as well. Some issues are purely caused by the installers. We are not going backwards anytime soon, so be it as it may don't use newer material and eventually get left behind.


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## rwh (Dec 17, 2014)

GAN said:


> Oh my goodness. Try to use M copper in part of my area and see how long it lasts before pitting & leaking. PCV, CPVC, PEX type L or K is the only thing that will hold up.
> 
> I assume your speaking about water service not DWV. I am seeing more CPVC and some PEX in my area, time will tell. Some 20 years ago the developer I was working with did multiple 4 family adaptable units, all cpvc. The only real issues we had or they still have to date is conversion at tub valves and frost proof sill cocks. As long as it was a cpvc male no problem, cpvc female adapters tended to split. Still holding up.
> 
> ...


You mean Chicago?


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## chonkie (Jul 31, 2014)

Funny Bill mentioned the photo they used and pointed out what wasn't good. I've had an issue with the pic they use on the front page talking about plumbing for people with disabilities or something like that. Here is the pic they use so you don't have to go look at the front page. Notice anything dangerous?


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## The Dane (Feb 19, 2015)

chonkie said:


> Funny Bill mentioned the photo they used and pointed out what wasn't good. I've had an issue with the pic they use on the front page talking about plumbing for people with disabilities or something like that. Here is the pic they use so you don't have to go look at the front page. Notice anything dangerous?


People with disabilities? No grabbars by toilet and no wheelchair access to lav because of a stupid box under lav. I would not go with glass doors for shower since disabled people are at high risk of maybe falling and breaking the glass.

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## Wes.booth (Sep 20, 2017)

rwh said:


> BTW, cpvc and PVC is as hack as it comes in residential.


How is using cpvc in residential hack?


Don't tell me you still use copper specially on a private well with conditioning equipment. Get with the times dude.


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## rwh (Dec 17, 2014)

Wes.booth said:


> rwh said:
> 
> 
> > BTW, cpvc and PVC is as hack as it comes in residential.
> ...


I would use PEX or copper, dude. Cpvc is ****. Used by home owners and hack contractors. Schedule 80 in industrial applications is another thing entirely.


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## GAN (Jul 10, 2012)

rwh said:


> I would use PEX or copper, dude. Cpvc is ****. Used by home owners and hack contractors. Schedule 80 in industrial applications is another thing entirely.



The industry is going downhill. One has to remember we have Galvanized, Copper CPVC, PEX generally. All are approved for Potable Water. I have seen multiple cases where copper gets pitted internally from micro-chlorine deposits, or out side from acidic ground. I have a town locally that inside any building you must have type L copper at least, type M is not approved.

I used to hear the same thing when PVC first came out on how much of a hack job it was. Very few places still require cast iron and a there are a few instances where you really should use it. Even though it is subject to rotting out with sewer gas and not being as smooth which can cause stuff to deposit in it. Or flat rust out where it gets snapped.

Not my favorite pipe by far and yes CPVC is a no brainer for homeowner's etc.

Back some 20 years ago while working for development company and them insisting on the cheapest code approved route to go I did about 10 4 family units in CPVC. Downside you need to be real careful with mechanical joints as they will split easily (always CPVC male into copper female). Today they make manufactured conversion fittings which are a step up. Now realize I am talking the days before PEX was on the market. These units are still holding up today. You have to real careful about support and allow for expansion with CPVC.

I wouldn't just throw it in with hack jobs though.


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## rwh (Dec 17, 2014)

GAN said:


> rwh said:
> 
> 
> > I would use PEX or copper, dude. Cpvc is ****. Used by home owners and hack contractors. Schedule 80 in industrial applications is another thing entirely.
> ...


I'm not resisting change at all. If the situation warrants non metallic supply piping, in a residential setting, I would opt for PEX. No one ever said "glad to see the piped this house in cpvc, they knew what they were doing." More like: when is this going to snap in half???


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## GAN (Jul 10, 2012)

Last time I had used any was well before PEX was on the market. For sure PEX before CPVC today.


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## Wes.booth (Sep 20, 2017)

Cpvc all day. Pex is garbage. It looks like garbage, reacts like garbage, and is rediculously frustrating to install unless you just dont care what it looks like. If you know what youre doing and can plumb worth a damn cpvc is great. Ive put in tons of it and have yet to have a problem. I mean not one problem. Dont use all plastic adapters and keep it away from places that will freeze.


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## rwh (Dec 17, 2014)

Wes.booth said:


> Cpvc all day. Pex is garbage. It looks like garbage, reacts like garbage, and is rediculously frustrating to install unless you just dont care what it looks like. If you know what youre doing and can plumb worth a damn cpvc is great. Ive put in tons of it and have yet to have a problem. I mean not one problem. Dont use all plastic adapters and keep it away from places that will freeze.



I lloooove sweat copper. In my part of the world it works forever. Sometimes other factors come into play, water quality and cost. Usually is cost. If I need to run non metallic pipe in a home, it will be pex.


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## Tommy plumber (Feb 19, 2010)

WashingtonPlung said:


> In washington PVC isn't even allowed for indoor use. You may use CPVC but it's so becomes so brittle over time that I don't know any one who would install it.


 










Same here in Florida. I suspect it is similar in all other states. PVC cannot be used inside the footprint of a building for water supply. It is not rated for hot water. 

It is however used extensively outside for water services but never allowed inside. And when I do occasionally see it inside, I know that I am following behind a handy-man-hack.


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## 5onthefloor (Sep 13, 2017)

Hate servicing CPVC and you'll run into it here in TX. Apartments will run 2" into the buildings and branch off to 3/4 and 1/2. 
I remember I helped a journeyman repair a 2" CPVC line that had flooded an apartment. We make the repair, and he gets impatient and wants to turn water back on. I remind him that the cement instructions say to wait at least 2 hours to repressurize. It had been like 45 minutes. He says I'm the lead do what I say. I tell him I'm not turning on water that he can do it. 
He grabs meter key, turns on the water. Comes back inside and he says See what were you afraid of...
Then it happens...a slight creak, the fitting starts slipping then BOOM! glorious geyser as that 2" main dumps out that water at 60 psi. Of course I grab the key and run outside to shut off water. 
Hilarious 

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## GAN (Jul 10, 2012)

5onthefloor said:


> Then it happens...a slight creak, the fitting starts slipping then BOOM! glorious geyser as that 2" main dumps out that water at 60 psi. Of course I grab the key and run outside to shut off water.
> Hilarious


Question, did you leave any valves open to bleed the air out. You know since water doesn't compress under regular street pressure you can have an air bubble with ten times the incoming water pressure trapped. May have helped.

I've seen videos of a 6" yard sprinkler line (golf course) when an RPZ on a air & water filled line slammed shut. created a pressure ripple and lifted sections of the line out of the ground.


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## 5onthefloor (Sep 13, 2017)

GAN said:


> Question, did you leave any valves open to bleed the air out. You know since water doesn't compress under regular street pressure you can have an air bubble with ten times the incoming water pressure trapped. May have helped.
> 
> I've seen videos of a 6" yard sprinkler line (golf course) when an RPZ on a air & water filled line slammed shut. created a pressure ripple and lifted sections of the line out of the ground.


It was like 8 years ago, but I seem to remember we left faucets and hose bibbs open. I just chalked it up to not letting cement dry but I can see how an air bubble could've caused it too.
After that I never let anyone pressurize a repair I had done that had not dried long enough and haven't had a problem since

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## skoronesa (Oct 27, 2015)

Pex hands down. We regard pvc water lines as being done by hacks. I understand in other parts of the country pvc water lines are the standard but not here. It gets brittle, cracks, or the joints fail. We avoid touching it at all cost and let the homeowner know that it is a liability. Most of us would rather replace a pvc line to an appliance than risk having a connection to it fail.

Pex doesn't get brittle or crack. Now rodent problems on the other hand.....lolz

I so badly want to video tape a pex line with peanut butter on unregulated city pressure just to see that look on that mouses face!!!


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## Tommy plumber (Feb 19, 2010)

5onthefloor said:


> It was like 8 years ago, but I seem to remember we left faucets and hose bibbs open. I just chalked it up to not letting cement dry but I can see how an air bubble could've caused it too.
> After that I never let anyone pressurize a repair I had done that had not dried long enough and haven't had a problem since
> 
> Sent from my SM-G930V using Tapatalk


 












I wait {25} minutes for CPVC to set up enough. Then I gently {slowly} open the water valve. Never had a problem. I only use the yellow cement. Maybe you guys used the orange cement?


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## 5onthefloor (Sep 13, 2017)

Tommy plumber said:


> I wait {25} minutes for CPVC to set up enough. Then I gently {slowly} open the water valve. Never had a problem. I only use the yellow cement. Maybe you guys used the orange cement?


I've never used the orange stuff. It might have been less than 45 minutes can't remember. Also could have been how he opened the valve since I told him I would not. I just remember that fitting popping off and flooding the downstairs apartment unit. It was hilarious 

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## dhal22 (Jul 30, 2010)

Pex only here, cpvc is hack work. Cheap, looks cheap, brittle and a kindergartner can do it. We still do a lot of copper though.


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