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Swimming Pool Plumbing: Rigid PVC vs. Flexible PVC, Which is Better?


Swimming Pool Plumbing: Rigid PVC vs. Flexible PVC, Which is Better?

By:  Jason Hughes

PVC pipeVisit any online pool and spa forum and you'll find that a leak is one of the most frustrating experiences a pool owner can have.  Finding, fixing, and not to mention paying for a leak will make anyone want to pull their hair out!  Needless to say, a pool builder needs to use the best installation methods and building materials available to prevent leaks along with all the bloody consequences that follow.  Today I want to turn our attention to the most fundamental component of a pool's plumbing:  Polyvinyl Chloride tubing....or PVC pipe.  There are two primary types of PVC pipe used in residential inground pool construction today:  Rigid PVC pipe and Flexible PVC pipe.  Let's compare these subterranean tubes to determine which you would rather have under your pool patio. 

What Rigid PVC and Flexible PVC have in common:

  • Rigid PVC and Flexible PVC pipes both have essentially the same chemical make-up
  • Both are cut and glued using the same tools and solvents
  • They are joined together using the same PVC fittings

What makes Rigid PVC and Flexible PVC different:

  • Rigid pipe, just as its name implies, doesn't bend on its own. This means whenever a turn in the pipe is needed, the installer either has to cut the pipe and install a fitting or heat bend the pipe to get around the turn. Both take time and varying degrees of skill.
  • Flexible PVC is made with plasticizers that make it softer and highly flexible. When a turn in flexible PVC is needed the installer simply forms the pipe around the bend and keeps on rolling. This method of installation is much quicker and easier than using rigid PVC pipe.

So far, we can basically see that we have a choice between a pipe that is stronger and more difficult to install verses one that is weaker and easier to install.  All things being equal, I'm going with the one that's easier to install!  But alas, things are never quite that simple, are they?  Here's the deal:

Flexible PVC pipe is much easier to install, but should never be used on an inground swimming pool....period!

Why Flexible PVC pipe should never be used on an inground pool:

1.)  Several years ago while attending a seminar on inground pool plumbing the instructor passed a small section of pipe around the room.  When it finally came around to me I was astonished!  It was a piece of 2" flexible PVC pipe with dozens of tiny holes in it.  My first thought was: 'What the heck?'  Then the instructor said one word....."Termites!"  Flexible PVC pipe is simply not suitable for underground use, but don't take my word for it:

Kuriyama of America, a large distributor of flexible PVC states:

"....Spa Hoses (flexible PVC pipe) can be damaged by rodents or insects, including termites. Spa Hose should not be used underground in areas infested by termites.  Our warranty does not cover damages caused by them...This product warning shall be given to every purchaser of Spa Hose. (Rev. 7/98)" has this at the bottom of their flexible PVC page:

"Note: Spa Hoses can be damaged by rodents or insects, including termites."


Do I even need to ask if you have termites?  Does it really matter?  Why would you take the chance?  The more appropriate question is:  Why would a pool builder take the chance? 

2.)  Flexible PVC pipe is much easier to puncture or crush than rigid PVC pipe.  It's simply not as strong, and considering all the pressures exerted on underground pipe, strength is a good thing!  I have seen "flex pipe" crushed and punctured both during construction and while working in a yard with existing pipe in the ground.  Anyone digging in a back yard needs to use caution, but personally, I would feel much more comfortable digging in a backyard that I know has rigid pipe versus flex pipe. 

So Why is Flexible PVC used on Inground Pools?

Although the swimming pool contractors that use flexible PVC on inground pools are in the minority, they are out there.  I believe and hope it's because they don't know any better.  There's no doubt that it saves time, and we all know that time is money.  The real question is: ‘Will you have it in your back yard?'  Needless to say I wouldn't and neither will any of my customers!  The last thing we need is to feed the termite population and waste our time finding and fixing leaks!  Please feel free to comment below and don't forget to subscribe to our blog before leaving.  Take Care! 

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Can you please speak a little about the heat bending method, and the possible problems that may occur if done improperly? Also, does the application of heat alter the "rodent resistant" properties of rigid pipe?
Posted @ Sunday, December 06, 2009 6:58 PM by Jim Assurian
Sure Jim, great questions! 
We heat bend our 2" rigid pipe using a hand-held propane torch or "wand". We lay a 20' section of pipe on the ground and run the torch up and down the section staying a minimum of 6" away from the ends of the pipe to ensure they do not become distorted. We constantly roll the pipe over with our foot to heat it evenly on all sides. After several minutes the section of pipe is like a 20' piece of spaghetti. I need to get a video of the process.....hopefully soon. The most difficult part of the process is heating the pipe evenly. If too much heat is applied to an area it will scorch, and quickly. If the pipe is not heated equally it will not bend properly and try to "kink". One other pointer: never attempt to cut and glue a section of pipe in the area that has been heated. The process distorts the diameter of the pipe and will most likely cause a problem connecting with a fitting. This is why we stay 6" from the ends. Regarding the rodents: Several years ago I personally asked Skip Phillips, former president of NSPI (the pool industries trade organization) if heat bending rigid PVC pipe has any adverse effects on the strength or durability of the pipe. He responded that it did not. Once the pipe cools to normal temperature it regains its structural properties. This would include deterring rodents or termites. Thanks Jim. Keep’em coming!  
Posted @ Sunday, December 06, 2009 9:53 PM by Jason
Ted Baudendistel( of Trilogy Pools wrote the following comment: 
Marcus / Jason, I read, with interest, the latest blog concerning flex hose (sometimes referred to as "pipe"). I too have verified the information specifically pertaining to termite-related risks. There are a couple more. 1. Flex hose/pipe surges just like a hose in your driveway will when you turn the water on. Over time, the flex hose will become worn in areas of higher stress or exposure to rigid backfill. Eventually, it will fail and leak in those areas. 2. There are bonding issues between rigid pvc and flex hose. Those joints are not as secure/permanent as rigid-to-rigid glue joints due to the difference in the chemical makeup of rigid pvc and flex hose. It's such a reoccurring and important topic, that I thought I'd send you a couple of thoughts. Ted  
Posted @ Tuesday, December 08, 2009 9:43 AM by Marcus Sheridan
Thanks Ted, great points. I have found that the glue welds do not hold as well either.
Posted @ Tuesday, December 08, 2009 9:52 AM by Jason
I have been building fiberglass pools for 24 years with flex-pipe PVC used for the connections around the shell. The area where I have built the majority of my projects has one of the highest concentrates of termites in the United States and have NEVER had a problem with termites or insect damage. The other problem in the West central Florida area is underground sink holes and ground movement, the flex pipe allows the pipes to move preventing damage to the shell and the wall connections. This is truly a myth like a fiberglass pool will suddenly float out of the ground. I have over 3,000 pools installed with flex-pipe installed around the shell. Some of features on the pools require the use of flexible piping to make connections to spa jets etc. The proper glue is required we always use the Rain & Shine Blue glue for all of the connections around the pool and the flex requires a few tricks of the trade for proper connections and working practices but it performs very well when installled properly. Remember most all of the skimmers wall fittings known as white goods are ABS material and not PVC and require special attention to make proper connections.
Posted @ Sunday, December 13, 2009 9:25 AM by Curt Prystupa
Thanks for the feedback Curt. Seems like you've had great success with flex pipe and I certainly wouldn't change a thing if I were in your shoes. I'm simply stating my opinion that rigid pipe is superior to flex pipe for underground use. I base my opinion on the statements by the flex manufacturers and the piece of swiss cheese pipe I held in my hand. There are also thousands of pools installed with sand backfill without any problems, but I say that gravel is superior. I look at in terms of which building material involves the least risk. With regards to the sinkholes and underground movement, the plumbing that moves in these cases is normally not damaged, regardless of whether it's flex or rigid pipe. What is damaged is the thru-wall fitting that is pulled down by the plumbing. We have found that tying our plumbing to the coping of the pool for support and using gravel backfill virtually eliminates the possiblity of any plumbing settlement. Thanks for the comment Curt. With your experience we hope you continue to offer your opinion and add value to our ongoing dialoge.
Posted @ Monday, December 14, 2009 9:53 PM by Jason Hughes
I developed a suction problem last summer in my in ground pool. My installer told me he felt it was a termite problem. I started digging and sure enough, my skimmer line flex pipe was riddled with bug chews. My floor drain line also had a few bites. My return line which is next to the other two lines was left alone. My installer came out and replaced the two lines with new flex pipe. I flooded the trench with 5 year termite killer and back filled. After 1-2 months, I again developed a suction problem. I closed the pool for the winter and just this week dug up my underground lines. Sure enough, my skimmer line was again destroyed by bugs. Although I'm not sure of what is eating my lines, I know I'm tired of digging them up. I removed all the flex that wasn't below cement and replaced it with rigid PVC. I'm praying I won't need to remove the flex pipe that's under cement. 
My pool guy says he has replaced enough flex pipe he's convinced there is an issue with this stuff. He has gone back to the black poly pipe on all his installs.  
Posted @ Saturday, May 15, 2010 6:47 AM by Steve
Sorry to hear you've had these problems; hopefully they're all behind you. Appreciate you sharing your experience. With any luck it will prevent someone from having the same issues. 
Posted @ Saturday, May 15, 2010 9:47 PM by Jason
Last year I noticed that I could not bled the air out of my inground pool pump. I checked to see if any of the conections has leaks. None of them did. We started to dig, and found 5 out of 6 pipes leading from the filter to the concrete had mulitible tiny holes. All 6 pipes were replaced. Now just a few days ago I am having the exact problem as last year. We even had a Termite inspection of the house and yard, and were told there was no visiual sign of termites. How is it that the pool company is not responisible for using materials that are not suitible for inground pools? Yes is it an easier way in install the piping and less expensive, absoulutley, benificial for the pool owner not really. How many cases are there out there? And why should it be the homeowners responsiblity for repairs when the piping should be hard pvc of underground work? Who should be responsible? Pool Company or Manufacturer?
Posted @ Tuesday, July 20, 2010 11:10 AM by Terri Taylor
I talked to my distributor in Ct. today just to find out if I was in the "minority" of those using flex pipe underground. Amazingly, they gave me the actual quantity of materials sold last year ( I'm a good customer and they do those sorts of things for me- and I don't like to bloviate without support like some do in this forum). 
They said last year that they sold 755 - 100' rolls of 1 1/2" flex pipe and 1,135 - 20' lengths of 1 1/2" rigid schedule 40 pvc. Let me complete the math for everyone. The total footage of flex pipe equals 75,500' and the total footage of sch. 40 rigid equals 22,500. I'm gonna go out on a limb here and say that your sources apparently don't do thier homework. If they would like to talk to my supplier I will not post there name and phone # here but they are in the Hartford,Ct area. By the way, flex pipe can withstand a freeze condition. Not that there should be one, but sometimes spa customers loss power and guess which pipe breaks first? Thats right "experts" the pvc! Now why haven't I seen any " 
experts" mention the regional differences in the use of each type of pipe? More evidence of incomplete research. I know termites thrive in the sandy soils that are more prevalent south of where I work. Why doesnt anyone mention the fact that flex pipe ensures that the pipe will "home run" from the pool to the filter slab without the use of multiple joints as would be the case for rigid sch 40 only available in 20' lengths? The more joints the more leak potential because of those joints. And how about friction loss with the addition of elbows when using sch. 40 rigid pipe? One 90 degree elbow can cost up to 3-5 gpm of flow with a 1 hp pump. I'm sure the experts have a valid response for that. One more thing. If there is anyone in the pool business that doesn't challenge the homeowners use of chlorine tablets being added to the skimmer then they in my estimation have no right to add in there 2 cents on this piping issue! How about the fact that when the pump is off and the chlorine being heavier than water will seep down the wall and eventually wrinkle and degrade the liner OR at least be a hazard when emptying skimmer baskets?  
Please save all the emotionally driven hysteria and deal in facts folks. If flex pipe was the big bad plumbing demon you make it out to be I would have been out of business 1,000 pools ago. FYI- I don't like finding and fixing leaks either. I've had one instance of termite damage in 1,000+ pools and that was due to the area being all sand soil. 
Posted @ Friday, July 23, 2010 2:20 PM by Pat McDougall
Well this ongoing debate has helped me tremendously and I appreciate everyone who chimed in here. 
To start I am not a professional pool installer I am a homeowner that through necessity have become an "armchair pool expert". My inground pool is about 20-25 years old and has rigid PVC around the pool except for one return line which is Flex PVC.  
My problems started when I decided to build a new deck. I also decided to run some new pool line for the return that never worked. It suspect that years of bad pool maintenance/closing/openings for winter ruined and burst they were "fixed" or should I say butchered. Currently I have everything for pipe. I have the rigid, poly and flex...a hodgepodge of frankenstein fixes by repair people who don't care. So I decided to repipe the entire pool so I at least know what and where the pipe is. My main drain is also gone. I know it was there...before the current liner was installed..I can see the outline of it underneath the liner.....Anyways sorry to be long get the picture of the mess I'm dealing with... 
So to make a long story short I decided to re do all of my lines and bury they 2 feet down along the pool deck using Flex PVC. I live in Toronto Canada and the soil here is clay not sand. One of the return lines is already Flex PVC and it has been underground for probably 10-12 years and it isn't leaking. So in my case (no termites) After reading your responses I think I will go with the Flex PVC because if I use Rigid I'm afraid it will shift and crack with the winter thawing/freezing/shifting of the ground. Am I wrong? The Flex PVC seems much stronger than the Black POLY as far as withstanding the weight of soil on top of it...
Posted @ Saturday, July 24, 2010 2:55 AM by Darryl K
Update on my above post. 
All flex that is not under cement has been removed. We found several "bug chews". No termites have been found but, several ant colonies have been found in the area of the flex. As the above post mentioned, my pool was back filled with sand. I still have a leak problem with my skimmer line. I lose approx. 3/4 inch of water every night. That's approx. 225 gallons. The leak is much less if the pump is left running. I'm unable to vacuum due to a lack of suction. We're trying to limp through the rest of the pool season and then all of my concrete is going to be removed as well as my liner so we can replace all the flex lines. 
Pool installers in Michigan only warranty their work for the first year. So unless the bugs destroy the flex immediately , the homeowner is the loser. 
My pool guy has had several problems using flex and has given up on it. Whether it's the flex, or the sand back fill causing the bug problems makes little difference to me. My pool is FUBAR. 
I also would like to note: my pool guy is still in business and is now quite busy with chew repairs.
Posted @ Sunday, July 25, 2010 8:41 AM by Steve
@Pat McDougall: 
My discussions with pool installers here in northern Vermont bear out with what you say (minus the hysteria accusation ;-). Up here, even with sandy soil conditions, we don't have termite problems. We do have constant ground movement due to freeze/thaw cycles, and flex pipe is reputed to survive better in the long term.
Posted @ Thursday, August 12, 2010 9:00 PM by Sim
I have a 10 year old jacuzzi spa, 
the flexible PVC is springing leaks lef and right, Most have been on the suction side so they are not even under preassure.  
It is a difficult situation because everything is glueed to everything else and not a lot of room. No termites. Just small cracks in the middle of the pipe.  
Has anyone else seen this?
Posted @ Friday, March 11, 2011 1:45 PM by Steve
Although flexible PVC I have used for years, until now that I have read your article which proven true an correct. I have learned a lot from this. thanks.
Posted @ Tuesday, April 05, 2011 7:41 AM by local plumber
Flex pipe is out for me. My trouble started two seasons ago but has only actually been realized upon opening this year. 
It all began with losing the skimmer-never could prime. We assumed it was blocked but repeated attempts to blow it out failed. Yes, even the pool pros could not clear it. Then I started reading more and more and found out it was possible that flex pipe could collapse. I suspect this is the case but as of yet it is unconfirmed b/c the pipe is under the concrete deck. 
Then we realized we were losing water. I could actually see water near the equipment pad so I dug up the area and confirmed 3 of the 5 returns were leaking in the flex pipe-no signs of termites though. 
After plugging all returns the pool was still losing water-an inch every 6 hours. Finally, I plugged the main drain and we're no longer losing water. So now I have no main drain and no skimmer. 
I am convinced that flex pipe is the reason I am having these problems. I am the second owner of the home and I know the pool was neglected prior to our use so there could be other contributing factors. 
It looks like I have a lot of hard labor coming up to re-plumb what I can get to after removing the concrete deck. Still not sure what I will do-if anything-regarding the main drain. Either way, I will only use rigid PVC from here on out. 
Thanks for the great info!
Posted @ Thursday, May 26, 2011 2:20 PM by Scott :: Atlanta, GA
Hey Scott, 
I couldn't spot my bug chews until my pool guy pointed them out. It was one of those moments where I went.. " I see!". The chews were small and always on the underside of the flex pipe. I saved a section of bad flex and can email photos if they would help. 
As far as the main floor drain line goes, mine was replaced a month ago while the liner was replaced. I was told now was the time as I would need a new liner after swapping out the drain lines. They pushed a new drain line down the side of my pool wall form and then broke through the cement next to the floor drain to connect the new line to the drain itself.  
Posted @ Thursday, May 26, 2011 5:35 PM by Steve
I have a pool that was installed 25 years ago. The installer(who was killed in a car accident 1 year after my installation) used both a combination of hard and flex 11/2" and 2". My pool started losing water about 5 years ago. Then it continued to get worst over the years. Next the skimmer suctions started to go down. Finally I cut open my deck to take a look at one of the skimmers. The flex line going to the skimmer was actually crimped into a near 30 degree crimp. The line would have had to lengthen about 12" for this to happen. At the crimp and near the 90 to the skimmer I had holes in the line that were losing water and the crimp was what was stopping the suction. The other skimmer was also not suctioning very good so I cut out that deck and the same thing on that side as well including leaks in the flex at the crimp and at the 90, including the 90 was cracked from the pressure of the crimp. When you hold a piece of the flex up to the light you can see light coming through in between the ridges in the flex. I tried jamming a small screw driver into to these valleys but could not pententrate into the pipe, pretty tough. Has anyone had the same experience with the flex growing and crimping??? There is no terminite damage, the holes were failures from the inside from the crimping and water wear or solvent glue attacking the pipe from with in. I pressure checked my return and supply on my spa lines with 10 psi of air and they held the test. I noted near the pump slab the installer again used flex for about 7' to make the connections easier for him to the pumping and filter. When I uncovered the lines all flex lines were laying flat. Later some of the line were bowing up once they were no longer covered with soil, like they were growing. One additional comment. When I went back to glue onto the old flex lines the fittings would not fit the flex any longer. I had to debraid a good amount around the pipe in order to put my coupling onto the pipe. The next question does the pipe expand as it ages? I know I will have to eventually dig up all my pool deck inorder replace the flex piping. I would not reccomend flex piping to any one and I will sure not use it on any thing in the future!!!! I have pictures of the crimping if anyone is intersested in seeing them. I know the installer did not install them this way because I saw them before covering and pouring the deck 25 years ago. Definite no for flex, beware of installers wanting to use this product.
Posted @ Friday, May 27, 2011 5:13 PM by Marley Bruns
I had my old rigid PVC replaced last year due to a crack from wear and tear over 35 years, with flex PVC and decided to run it outside of my cement decking "just in case." Well good thing I did b/c after last summer I have had it! My pool guy came back 5 separate times to fix leaks and neither one of us could determine what the heck was making the little holes. Just opened last weekend and two fixed leaks already with the same chew marks and holes. A friend mentioned termites and thanks to your blog I will look into it more but looks like I'll be replacing again this year but going back to the rigid PVC that lasted 35 years!
Posted @ Tuesday, June 07, 2011 8:40 PM by MaryAnn- Albany NY
I am in the early design stage of my inground pool and this discussion has been a big help. It seems to me rigid PVC is the way to go, especially here in SC. My question is: what is the recommended strength of the PVC? Schedule 40 or 80? Thanks in advance!
Posted @ Saturday, June 25, 2011 7:12 PM by Clarence Eugene
why would anyone want to use flex when rigid is only a couple of connections away from being almost as easy to install??? that fast-man stuff will get you or your customer in trouble every single time. class a general contractor virginia...i never cut corners & thats why things seem to always work out pretty good for my business.
Posted @ Thursday, July 21, 2011 8:46 AM by thomas richardson
I have an in-ground pool that was plumbed with flexible PVC about 20 years ago. Now the return piping from the in-line chlorinator seems to have been attacked by the chlorine, and the diameter of the pipe has been restricted to about 1". I am assuming that I will have to replace teh entire underground return line. Have you ever experienced this degradation of flexible PVC? Is it driven by highly chlorinated water, and will the rigid PVC have the same problem? 
What are your recommendations?
Posted @ Tuesday, August 02, 2011 10:25 AM by Rob Taylor
I live in MA. do not have sandy soil, inground pool is 25 yrs old. my skimmer started sucking air about 5 yrs ago, there was a leak somwhere in the original black poly, wasnt about to bust up alota concrete patio to find it! so it was replaced with flex line running it around the patio to the filter. the very next season i was sucking air again, the only area of concrete that had to be busted up to get the flex line attatched to the skimmer is only about 5' long to the edge of the pattio, well that of course is wear the new leak was... busted up the concrete again, cut out a 3' section of the line that had several 1/8" size holes in it, precise holes like a drill bit, my pool guy said it was termites! i've had problems every season with this problem, lots of patches in the flex line now! we had tyreatment for termites last summer, suposed to be good for 12 yrs. no termites or damage was found in the house just around pool and shed... but i keep getting the termite holes in my flex line, i patched one just yesterday, and i'm still suckig air! i will be contacting my pool guy and ripping out all the flex line from the skimmer! going back to poly or rigid... breaking up concrete and digging up the lawn every yr for the last five yrs... is enough for me!
Posted @ Saturday, August 06, 2011 8:08 PM by bob
I have been building pools for 44years and have used flexible pipe for the last 22 years and never had a problem Perhaps we don't have such  
nasty Termites in our country. the only point we are not sure is the affect of ozone on flexible pipe.We are told ABS is ok with ozone but it contains Nitrile which is a form of rubber can not find the composition of flexible pipe any were Can any one help?
Posted @ Sunday, September 04, 2011 8:36 PM by Kevin Julian
I'm building my own gunite pool and was intending on using flex pipe in the areas that were to be encased in the gunite and then use rigid pipe everywhere else. Is this method acceptable? i would love any feedback on this process along with what exact type and size pipe i should use for the best performance.
Posted @ Tuesday, January 03, 2012 2:24 PM by Otis Himes
I would not use flex in that case as it has a tendency to jerk and shift as the pump turns on and off....this can actually wear through the pipe over time.  
Regarding pipe size, that's a complicated question, I'd suggest checking with the pump manufacturer to finalize that as they can help you calculate flow rates, line velocities, friction loss, etc. based on your specific circumstances. We use 2" on most of our stuff.  
Good Luck!
Posted @ Tuesday, January 03, 2012 2:47 PM by Jason Hughes
Am I glad I found this site, my pool builder has used a mix of flexible and rigid pvc. The gunite pool is largely above ground and I was planning re-routing some of the pipes in the ground to tidy things up a bit. The builder says flexible deteriorates due to chlorine. 
Have not asked him about termites yet which we certainly have around here(Spain). It is about time the tech boys came up with a material that bugs don't like. Thanks to all 
Posted @ Tuesday, February 07, 2012 7:29 AM by mike
Gunite pool. Skimmer suction not good. Leak. Narrowed to flex connection to skimmer. Flex in the gunite wall. Need to cut deck bypass gunite wall and connect rigid to flex down the line.
Posted @ Friday, February 10, 2012 1:07 AM by bob duerr
I used a single piece of flex above ground near the equipment slab, and wrapped it in black tape to avoid sun damage. Special glue for flex PVC was used, and there was no vibration on this pipe. Three years later a leak developed near a fitting, in one of the pipe grooves. When I removed the section, the pipe had become extremely rigid.  
As a novice homeowner-fountain builder, I didn't have resources for advice beforehand. But with specialty fittings such as 11 and 22 degrees elbows, double 45 elbows to go around pipes and long sweep elbows it should be possible to plumb any situation without flex. My advice would be to increase the pipe size so friction loss isn't an issue. If you're thinking 2" then go to 2.5" on the pressure side and 3" on the return. And wrap all pipe embedded in concrete with a sleeve or tape so that concrete cracks don't propagate into the pipe. All this costs money, but you don't want to ever have to chip out concrete years later.
Posted @ Monday, February 20, 2012 12:30 PM by Jon
Concrete pool with vinyl liner installed about 6 years ago in southeastern Massachusetts. Last year found leak in return line (by water loss method confirmed with pressure test). Naturally leak is under stamped concrete deck. Contractor used flex. Ground is glacial till with sand backfill. The contractor commented that usually the termites attack near the pump but not the case for us. Spoke to another local whose pool is same age, same contractor, same flex. Same problems except his holes are not under the deck. I would prefer to tunnel in from side rather than chop up a perfectly good deck but the 'new' contractor who will be fixing leak would rather cut the concrete (and have someone else patch it). The original contractor is offering nothing to either so far. 
I will repipe with rigid, schedule 80. Also, would consider a coating on the outside of the pipe if anyone has recommendations.  
Posted @ Thursday, April 12, 2012 5:57 PM by Dan
Had a fiberglass poll installed end of summer 2010. We really have only had a chance to enjoy pool one season. As we were trying to prepare pool for this season we have discovered we have leaks in plumbing. We lose 5 inches in 2 days. The contractor is saying saying his year waranty is over. Oh yeah, he use flex pipe and the pool is inground.Do you think I have a legal case?
Posted @ Tuesday, May 08, 2012 8:50 PM by cindy
I read and agree with the opinions on flex pvc. I am a not a pool pro and am trying to help a friend fix Her inground pool. Only problem I am having is how to secure the flex in a rigid pvc fitting ? looks like pool installer torched the end to get it pliant then shoved fitting on(with glue ?) I am just trying to help this lady out, She cannot afford right now to have new piping installed as She is widowed with 3 kids..Any help greatfully appreciated. Thank You in advance.
Posted @ Sunday, June 03, 2012 7:31 AM by Ray G.
Ray, to glue flex pipe you need to use a solvent (glue) that specifically states it can be used on flex pipe. We use Pool-Tite 2300, the blue glue. You can get it from a pool store.  
Good luck!
Posted @ Monday, June 04, 2012 9:45 AM by Jason
My pool is leaking due to damage caused by termites eating the flexible PVC. What recourse do I have against the builder?
Posted @ Tuesday, June 05, 2012 12:39 PM by Brigitte
I honestly don't know. You could talk to an attorney and see what he has to say. It would be the first suit vs a builder for using flex pipe I've heard of. Sorry can't be more help.
Posted @ Tuesday, June 05, 2012 1:47 PM by Jason
Well, the Orkin guy is here... I'm going to have to put the termite baits out for a year and when they are under control, rebuild the pipes. I don't think, from what I read here, that I have a chance of winning any lawsuits. We are in upstate NY and if the builder had used the rigid pvc, we'd be looking at a different problem with freezing, shifting and cracking. Thanks for the invaluable info!
Posted @ Tuesday, June 05, 2012 1:57 PM by Brigitte
We're having the same problem with damage to our flexible return and suction lines. Last year we repaired a portion of the return line but this year upon opening we discovered several more problem areas. We're going to replace everything with rigid pipe and are thinking of running them on top of the ground where possible. Do you think there is a problem with that? We live in Ohio but the lines are blown out each fall when the pool is closed. Thanks much for your advice - we're tired of chasing leeks.
Posted @ Tuesday, June 26, 2012 5:40 AM by Nancy
Termites are eating through my flexible plastic pipes just a few months after installation. I'm told that this will be an expensive problem to fix -- good news for the installers but not so great for me. Pool builders that use flexible plastic pipe deserve a costly class action lawsuit. I'll sign up.
Posted @ Wednesday, July 18, 2012 8:04 PM by Steve
Great info on here, thx to all. 
I have a suction problem,the pump is surging all the time with pressure at the filter swinging from zero to 10 or 15psi continuously. The area is North Toronto, in-ground pool installed 25 years ago by previous home owner. The ground is 100% sand! I replaced all the pool equipment and piped in rigid pvc. The underground pipes are flexible as they come into the pool shed. Reading here its quite likely the pipes are flexible all the way to the skimmer. We've been losing water each day as well so it all seems to point to a leaking flex pipe. Termites and huge ants are very prevalent around here too. At least we are in sand so the dig wont be too bad!
Posted @ Monday, July 30, 2012 11:47 AM by Steve
in ground pool - main pool drain pipe back to pump suction. When the pump is off what will be the level of the pool water in this line...will it equalize to the pool water level or should line remain full all the way back to the pump?
Posted @ Friday, September 07, 2012 8:32 AM by tom oconnor
The line will stay full until the seal is broken, like by removing the lid on the pump strainer pot for example, then the water in the line will equalize with the pool water level. If the pump is more than 12" above pool water level you might want to install a check valve on the suction lines to make life easier.
Posted @ Friday, September 07, 2012 8:49 AM by Jason
I am having a new liner installed and the skimmers and lines replaced before pavers are placed. 
A couple of contractors recommennd rigid PVC as the best way to replace the lines. The contractor I was hoping to use says that he only uses the black PVC with clamps and won't use rigid PVC because they are more likely to leak or crack because of 1)glued joints at every turn - if not glued properly/perfectly each time, 2)rigid pvc may break from any movement like settling, 3)black pvc is more forgiving if lines aren't winterized perfectly - rigid PVC will crack. And both are not damaged by termites. What do you recommend - rigid PVC or the black PVC?
Posted @ Sunday, September 30, 2012 9:47 AM by stu
I have to replace my filter, I'm no kind of plumber. I've chosen a Hayward EC75A DE filter, Hayward recommends the flex pipe. (My pipe right now is all rigid PVC.) Anybody foresee any problems if I use flex ONLY for above-ground connections? Thanks.
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Posted @ Wednesday, October 17, 2012 11:32 PM by Plastic Pipe Fittings
We have a 30 plus year old pool that we are doing major renovations on. New steps, new liner, new filter, some new concrete, some new plumbing. 15 years ago I used some new flex on return lines and Mother Nature has worked them to the surface. They still do not lead. The original builder over 32 years ago use cheap thin plumbing, but most still seems to be hanging in there. We have no apparent drain leaks, but the steps are cracked and leaking.The pool is 18 by 26 with two returns and one skimmer. Any suggestions.
Posted @ Saturday, March 02, 2013 12:36 PM by Louis Klemp
Louis, if you have access to the plumbing during this renovation I would replace as much of it as possible. It's a cheap to do it now...incredibly expensive if you have to later. Good luck!
Posted @ Wednesday, March 06, 2013 8:40 AM by Jason
We are looking at an in ground pool installation this spring. Does the fact that we live near Toronto, (Canada) and the winters can be brutal, make a difference on whether we use flex or rigid piping?
Posted @ Friday, March 22, 2013 1:37 PM by Tammy
This is a great topic that is covered time and time again. Rigid and Flexible are both good pipe choices all with their own grades and different properties. It depends on the application, but rigid is typically the pipe style used for outdoor / in-ground applications. Not always, but most often used.
Posted @ Monday, March 25, 2013 8:06 AM by Amanda
I meant to update my post from May 15, 2010 a while ago but forgot. After having all flex pvc that was not below cement replaced, the following season we again developed a suction problem. The only way to replace the flex below concrete then involved saw cutting sections of my sidewalks and even replacing the pool liner so the floor drain line could be replaced. This meant breaking out the gunite under the liner around the floor drain.  
I noticed the water moving through the flex pvc is quite loud I believe because of the ribs which allow flex. Perhaps the sound or vibrations are what lures the bugs. I should also note that no evidence of termites were found other then crews in the bottom of the flex. Ants however, were seen to have set up shop near my flex line. 
I wish I would have taken a closer look at the flex back when my pool was installed. This style of pvc is so soft you cut it with a utility knife as opposed to rigid pvc which requires a cutter or hacksaw. This was a several thousand dollar lesson I learned the hard way.
Posted @ Monday, March 25, 2013 10:16 AM by Steve
I have a salt water fish tank and using this kind of plumbing really helps. I use this to run the plumb off the tank to the sump/filter.
Posted @ Thursday, March 28, 2013 11:58 AM by Boston Plumbing
When something is hard to fix or revisit later, I tend to go the "cheap" route. That means I tend to use the overkill technique and not be concerned with the upfront cost. 
So what about using Schedule 80 rigid? You must use primer and a high quality, fresh PVC cement. Perhaps it would not lend itself to heat bending as easy as schedule 40 or at all, but the pool I am looking at has no curves. It will be indoors, however, and fully surrounded by concrete floor. This installation simply cannot fail for any reason.
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Posted @ Thursday, May 23, 2013 8:36 AM by Send sms
Regarding Schedule 80, it has a reduced inside diameter compared to Schedule 40, leading to poorer flow characteristics and higher friction loss. Therefore pipe size may have to be increased if using 80.  
All threaded fittings should be 80 for optimum strength.
Posted @ Thursday, May 23, 2013 9:43 AM by Jon
builders use flex for one to two feet from bottom of skimmer to the hard pvc then the pvc continues to the filter pump.Problem is flex collapses due to the suction over time wear on flex plus cholrine tabs in skimmer(unless they are bio guards smart sticks)also wear down the flex.i have a 3 hp pump down hill and a year later i have to beleive its collapseing from strng pump builder suggested?? have to dig it up now,not happy at all...its done this way as its easier to point the flex in any direction to the pump/filter...what else can be done.i work on older anthony pools and new anthony sylvan and they still do this.....helpppppp
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Posted @ Thursday, June 13, 2013 9:06 AM by French supplier of fenetres pvc alsace
termites/works previously filled my skimmer line with holes. Repaired with sch 40 rigid. Now, 5 yrs later, skimmer line is again leaking. It appears the bugs ate thru it too. Now, the question is, what to use for this repair? I thought perhaps sch 80, or pipe within a pipe and fill the area between with diazanon or other poison--but then fear the poison will damage the line and cause even worse results. Metal--not good, will rust and stain pool. I'm running out of ideas....
Posted @ Monday, June 17, 2013 4:27 PM by pec
Flex PVC pipe has kinked underground and reduced input flow to my pool over the years. The material isn't stable if used right after a pool heater. It moves around like a spaghetti noodle even 18-24" underground. I think ridged PVC may be the only solution but I wonder if it can resist the Michigan winters?
Posted @ Friday, July 05, 2013 3:07 PM by Dan
I've been in and around the Pool and Spa Industry since 1985. 
There are many issues w'Flex PVC, as outlined above. Also, when Flex is used directly from the bottom of a Skimmer, and then "swept down and across to the pump - you're asking for problems if you are of the "Tablets in the Skimmer Basket" school. 
When the circ pump switches off, the waster continues to erode the tablets and the resulting concentration of Tri-chloro- is brutal on flex pipe. Invisible from the outside, the concentrate leeches the plasticizer out of the flex and results in an ID of 3/4" or less. If anyone wants pictures, eMail me at It is truly horrendous. 
I don't promote putting tabs in skimmers for this and the bleached liner problems that result, but some people just dont want to spend a few $ to install an Off-Line erosion feeder...  
It's up to responsible builders to insist on it.
Posted @ Tuesday, July 23, 2013 2:56 PM by Greg Simmons
Thanks for the interesting article. If you were to take termites out of the equation. (not in the uk) which would be your preference. Mine has always been flex for the following reasons.  
Less joins thus less chance of leaks - temperature / skill / material failure.  
Flexible thus less chance of leaks in ground movement.  
Quicker install time.  
Reduced skilled labour.
Posted @ Wednesday, July 31, 2013 7:15 AM by Alex Kemsley
I have a leak in our main drain. Believe it is all ridged PVC. Was wondering if anyone has every tried Pipes Down Under to reline their pipes. It uses Flex line that can inside existing line and be glued into place even with water still in pool. 
I have seen this type of relining down with home drains but they use something similar to fiberglass and epoxy. 
Since it is the main drain I will dig up section that I can and check it first but if it is to far down I will have to wait for next time we Reline the pool. Just did that 3 years ago.
Posted @ Wednesday, August 07, 2013 7:01 PM by Peter
I am about to replace my 14 year old vinyl liner. For several years it has been difficult to vacuum my pool, lack of suction. Also, the outflow of my jets are not very powerful. Several years ago, I had a pool technician investigate the problem. The results, the HARD PVC was riddled with termites. I was able to see numerous termites in the soil. While I am replacing the liner I am going to ask that they replace the PVC lines. It was suggested that, in my case, to use the old black hoses. Opinions welcomed? P.S. Long Island soil seems to be a resort area for termites.
Posted @ Sunday, October 06, 2013 7:03 PM by Joe
Leaks are terribly frustrating, but please don't assume a pool builder is a crook or chiseler for having used flex PVC. Compared to rigid sch. 40, or poly pipe, flex is VERY expensive. It also has the virtues of poly (longer, flexible runs with fewer joints to break), combined with the virtues of PVC (glued exterior joints, larger interior diameter, compatibility with threaded and socket fittings). As a pool builder, I have been combining rigid and flex for years. I use rigid sch.40 for all vertical pieces (stand pipes), and flex for all lateral runs along the concrete collar at the bottom of the pool walls, which is about 3' below ground surface. I have to believe that depth is an issue with regard to termites. Sweeping down from a fitting with flex is never a good idea. Backfill will pull down on the pipe, making it want to rip out or crimp. I build vinyl lined pools which have an over excavation and allow for low runs of pipe. Gunite pools tend to be plumbed at the height of the fixtures in the pool, since there is no over excavation. I have experienced no issues thus far with my plumbing, but after reading some of these blog entries I'm concerned. The swimming pool industry has evolved significantly, especially in the past 10 years. Perhaps a better material or method will become available in the near future. For now, there are virtues and flaws with all plumbing methods. We, in this business, owe it to one another and our customers, to leave the industry better than we found it by sharing our experiences. Homeowners, please be mindful of flow rates and pump sizing, not just pipe material. Always seek advice from experienced people. Most will give it freely. Termites, go back to eating wood (or something else!) 
Posted @ Wednesday, October 23, 2013 2:29 PM by karl
I have a leak somewhere in my main drain line, my pool is concrete and is pretty old. What can I do for a temporary fix so we can use the pool this summer? Is it possible to snake something like flex pipe down the original pipe for a temp fix?
Posted @ Friday, June 13, 2014 11:53 AM by Tonja Ray
The only thing you can really do is remove the cover and plug the main drain line from inside the pool....that will stop the leak.  
Good luck! 
Posted @ Friday, June 13, 2014 12:05 PM by Jason
We thought about that, but wouldn't we also need to plug it from the other side at the pump area so water does go into and leak out from that side?
Posted @ Friday, June 13, 2014 12:14 PM by Tonja Ray
This may sound totally absurd but what about using both flex and rigid at the same time? Encase 1.5 inch Tigerflex hose inside 2 inch rigid, thereby gaining the benefit of termite protection and crush damage while ensuring steady flow within flex tibe that doesn't have the multiple coupling fittings. Just a thought.
Posted @ Monday, June 23, 2014 6:03 AM by Richard Hardy
Flex pipe has a curl and a rough exterior and would be difficult to thread through another pipe. And you would then need a straight run, eliminating the advantage of flex.  
I used rigid PVC with unusual angle and specialty fittings that I purchased ironically from! They have 11 and 22 degree elbows, sweep elbows, manifold wyes and dog legs for avoiding pipes at crossings. Using these you can plan a rigid line to minimize friction losses. If there are many fittings just upsize the pipe- it's only money and the goal is to minimize future problems.
Posted @ Monday, June 23, 2014 10:01 AM by Jon Savell
This may sound totally absurd but what about using both flex and rigid at the same time? Encase 1.5 inch Tigerflex hose inside 2 inch rigid, thereby gaining the benefit of termite protection and crush damage while ensuring steady flow within flex tibe that doesn't have the multiple coupling fittings. Just a thought.
Posted @ Monday, July 07, 2014 8:50 AM by Ramen leuven
I did that and it was the only pipe that failed. The flex cracked in a groove between the coils, either from vibration or sunlight. The flex had been installed only two years previously. I prefer rigid PVC with unions between every fixture, as it's easy to disassemble for part replacement.
Posted @ Monday, July 21, 2014 7:32 PM by Jon
I have a leak under my concrete.Flexible PVC was used.My pool is 14 Years old.The original pool contractor said I should probably replace it all at aprox 4000.00.Would you agree
Posted @ Monday, September 22, 2014 1:18 PM by
$4000 sounds too high. I was quoted $2500 for same job but contractor blew me off. So, I did it all myself, by hand. While not an easy job, I have only spent $200 in rental of concrete saw and lots of 2 inch rigid PVC. I also opted to replace pump and filter for $1100. It's a tough job to do by yourself (digging approx 100 ft of trenches) but I hate being ripped off by anyone, especially pool contractors who renege on their promises.
Posted @ Monday, September 22, 2014 5:46 PM by Richard Hardy
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