Should I Replace My Copper Pipes with PEX?

Leave a Comment - 9


Alan Couch

Subject: Copper water lines fail after 16 years

I built this house in 2000 and used copper because at the time, it was the best in my opinion. Now my lines are developing pin holes and I will replace it all with cpvc. I am on city water.


Subject: Absurd

The whole reason pex was developed was to drop costs for home builders. It's ABSURD that this system is being pushed as a retrofit. Pex is a downgrade system vs copper and/or cpvc. Pex cost $150/300'. That's 0.50c linear foot. A new whole house install (open frame) takes 1/2 day. A retrofit takes 1 to 1.5 days depending on system size.
My 77 year old neighbor is being sold a $10,000 contract by Craigslist service provider. For $500 investment, Plumbing CO. Gets $9,500 profit in 10 to 16 hours from 1 employee. Wow. They are victims & can't convince otherwise. Sad.

Johnny Bolt

Subject: PEX

PEX is too easy for mice and rats to chew through. Just google PEX rodent damage or similar terms. Way too many hits for something as important as indoor piping.

A mouse can get in your walls and climb through from the crawl space to the attic and that means it can chew a hole in ANY of the PEX anywhere in the house, in the walls, in the ceilings and depending on how long that leaks it can cause thousands or tens of thousands in damage.

Why take that risk when CPVC does everything we need pipe to do and is highly available and cheap enough. PEX is not magic pipe that install itself. Unless you plan on throwing the stuff right down on the ground you still have to hang it and ideally make it look kind of nice. You are supposed to be a licensed and skilled professional... right?

If your going to do anything that resembled a nice job of installing the pipe, the fact PEX Is highly flexible does not make it easier to install and can make it significantly harder to repair. I don't see any reason to use it knowing it's easily chewed through by mice and it's not really proven over a long enough period of time compared to CPVC.

The only smart use of PEX should be radiant pipe, but with so many reports of rodent damage I wouldn't even use it for that anymore.

CPVC is super easy. corrosion proof, well proven and easy to repair, stick with the proven product for something as important as the core infrastructure of your home or you will increase your chance for water damage or winding up with recalled tubing in your home like all those people with all the other failed flexible tubing water supply pipe throughout the decades.

The idea is not new and it has failed multiple times, play it safe and use CPVC.


Subject: Mice can chew through

Mice can chew through concrete aswell, so I believe any material used ¨could" be chewed through due to mice. The logic you have is flawed at best. CPVC is easily broken...I have personally seen more ¨broken¨ CPVC pipes than PEX and Copper combined.

Blake Duncan

Subject: 25 years of PEX

I've been installing PEX for 25 years and have NEVER had a failure. I keep samples that are plugged on both ends full of water (no air in them) and routinely beat them, frozen and thawed, with a hammer for customers and have not had a failure. I leave them with the customer and invite them to abuse them all they want under as many freeze thaw cycles as they want. ZERO failures. 25 YEARS.


Subject: flex cost savings

I had several leaks a couple of years ago and so asked about an option to replace the cooper which I had leaks the previous year. Flex was recommended as the solution, I agreed and within 2 hours the job was completed, five cooper lines replaced at a cost of over $900. I think that is a very expensive change for the material and time put into it. The work was done by a local plumbing company. Needless to say, I will never use them again. The reason I am on here now is that I now have a leak in my cooper shower line so i'm trying to learn to do it myself. I have no trust in the professionals to charge a fair price.

Nathan Graham

Subject: PEX fittings

A few years back I got a call on Thanksgiving morning for an emergency plumbing job at a low income apartment complex. Six different apartments had water flooding them from pipes in the ceiling. The contractor who built the buildings used unskilled laborers to install PEX with Sharkbite fittings. If you could do it wrong.....they did. They often times ran the plumbing on the OUTSIDE of the insulation, did not use elbows but instead just ran the PEX in a big arc in the attic, the heat for the apartments came from their individual hot water heaters that couldn't handle the the constant use in our sub zero winter climate, little to now insulation was used in the outdoor water closet, and the hot water heaters were installed so that the intake/exhaust were facing west, the direction the wind comes from more often than not (meaning, on high wind days the exhaust was forced into the intake, choking out the flame). Anyway, to get back to the point of this article, the PEX lines froze and broke just as readily as copper. It wasn't that cold that Thanksgiving but the combination of high winds choking out their hot water heaters, no insulation and multiple other factors caused dozens of PEX failures. And I found numerous sharkbite fitting that had failed, not just due to the freezing but simply because the plastic parts inside failed under pressure. While PEX and Sharkbites are good in a pinch (an emergency fix), I would avoid using them to plumb your entire home, especially if you do not know what you are doing.


Subject: Another 23 years

If there are pin holes in the piping it indicates there has been substantial corrosion of the copper pipes, and it may be close to catastrophic failure. it is unlikely that this is limited to a few locations, but is systemic.
This is a known drawback to copper pipes, if the water is acidic it can corrode the pipes, invisible from the outside they become fragile thin walls ready to burst.
If the original plumber suggested replacing, then replacing is probably the right thing to do and don't take the advice of someone who has never inspected the pipes over a professional who has seen them firsthand.

Toby Brenton

Subject: PEX

The only problem I have had with the PEX is we had a rat chew through one of the lines under our house when I was at work. Flooded the entire crawl space. Other than that, easy to install. Awesome product. Got to love mother nature.

View Comments - 9 Hide Comments

Post New Comment

Offers <
Popular <
Answers <



First - NOT full septic tank - if that was the case you would be getting backup of sewage into the lowest drains in the house, and possible very slow flushing or refusal to drain out of the bowl - the opposite of your case.

Second - I assume you are the owner. If a renter or on a lease, this type of problem may be the responsibility of your landlord, depending on the terms of your lease or rental agreement.

OK - two possible situations here - low water in BOWL, or low water in TANK. I am assuming your toilet flushes OK, with adequate water to clean out the bowl, and that it is a typical type toilet with a tank sitting on the back of the bowl. If this is not the case and it is a designer toilet or looks like those at public restrooms (no tank), then the BOWL answers still apply if it is initially refilling OK, but if not enough refill water coming in at all then call a plumber.

First, low water in the toilet BOWL case. If the water in the toilet BOWL is low after flushing, I see four likely causes, in order of most likelihood -

1) the fill valve is not putting enough water into the toilet bowl. If you take the top off the tank, you will see a small hose (typically black plastic) coming from the fill valve (a vertical mechanism, usually at left side of tank, that the incoming water tube or flex hose connects to the bottom of on the bottom side of the tank). While the tank is refilling after a flush, a steady but not large flow of water flows through this fill tube and down into a vertical pipe or tube (usually brass or plastic and about 3/4 inch diameter, which stands almost full height of tank). The small tube puts water into this pipe, from where it flows into and refills the toilet bowl. This is also the overflow tube, which keeps the tank from overflowing if the fill valve fails to shut off. If the fill valve has a problem or the fill tube has a blockage, it may not be letting enough water into the bowl. Also, check the tube is actually pointed down into the overflow tube - if the clip came loose, rusted away or broke, then it may just be filling the toilet tank rather than the bowl. Check that a steady flow (will not be a real foreceful jet) of water is flowing out of this tube into the overflow pipe while the toilet tank is refilling. You should also see the bowl filling up at this time. If it come in but does not fill high enough because it does not run long enough, some fill valves have an adjustment - check fill valve manufacturer website for instructions. Others just have to be replaced - doable if you are handy at home repairs (see web videos on how to do it), or call a plumber for probably about $150-200 to replace fill valve (have him replace the flapper valve at same time if you get this done).

2) there is something like a rag or string caught in the trap (the waste passage within the toilet body itself) which is slowly wicking the bowl water down the drain - would be solved by a good snaking. If this is the case, the bowl will fill fully after flushing, but then slowly (typically many minutes to hours) drain down to just filling the start of the oval or round drain passageway where the waste passage starts to curve up into the toilet body.

3) blocked sewer vent pipe (which vents sewer gas and lets air into the sewer system so when you flush the traps in drains and toilets and such do not get sucked dry by the vacumn caused by the exiting flow. If this is the problem, then several drains in your house may have the same problem, or drain slowly. When you flush, the water will drain totally down the pipe and almost all the water in the bowl and trap will go down the drain too, typically with a gurgling sound for a few seconds at the end as the air seal is broken in the trap, then a small amount of water will flow back from the trap into the bowl, leaving you with water in the entrance curve to the trap but nowhere near normal height in the bowl - maybe not even enough to fill the entrance of the drain passage.

4) a crack in the toilet, letting water gradually leak out of the bowl onto the floor or into the subfloor. If this has been going on for long at all you should see water on the floor, or water coming out in the ceiling downstairs, or in the basement or crawl space under the toilet.

Case 2 - the problem is low water in the toilet TANK - since this is a sudden problem, two likely causes:

1)  the float arm has corroded or the float setting has moved. Look in tank for any broken part. You may have a black ball on the end of a metal or plastic arm connected to the fill valve (which is the part, normally at the left side of the tank, that the flexible or copper tubing comes into at the bottom of the tank), or it may be a sliding cylindrical float that slides up and down on the fill valve (typically all plastic) - see if it is broken or loose or alll corroded up (for the arm type). When you flush, this float hangs down (if lever type) or slides down the fill valve (cylinder type), opening the fill valve so fresh water comes in to fill the tank and bowl. As the tank fills it lifts this float, till at the proper elevation the bouyancy of the float shuts off the fill valve. If the setting on this float has changed then it will either cause the toilet to "run" continually because it is trying to overfill the tank (float shuts off at too high a level, so water is continuously flowing down into the overflow tube and into the bowl); or it will shut off too soon, causing only a partial tank fill. There are adjustments to adjust the float shutoff setting - typically an adjustment xxxx on the arm-type, and a slider stop clip on a small rod for the sliding type. See web videos on how to adjust this, or call a plumber.

2) your flapper valve (in bottom of tank, the part a chain or cord or rod connects to the flush handle, which opens it when you flush the toilet, leaks. If it leaks AND the fill valve is working, the tank level drops till the fill valve opens, then the tank refills. This repeats at intervals, with the tank refilling periodically even though it has not been flushed. May need new flapper valve or just a good wiping of the sealing surface to remove grit that is causin it to leak. If this is the problem you will have a slight flow of water into the bowl continually, and will probably see a slight ripple in the toilet bowl.

3) water is leaking out of the fittings or bolt holes on the bottom of the tank. If this is happening enough to make you notice low takn water level, the tank will refill periodically the same as if the flapper valve is leaking, plus you will have water on the floor and dripping off the bottom of the tank.


Fill valve and flapper valves each cost around $15 if you do it yourself (you can buy just replacement flapper for less if that is the problem and the matching seal is good, but that is rarely the case). A plumber call to replace both probably $150-200, ASSUMING your water shutoff valve (at the wall, under the tank, with a flex or copper tube coming fromit up to the toilet tank) will work.. If it will not shut off the flow of water, then add another $50-150 to replace that, depending on how it is plumbed and whether he has to cut into the wall to replace it (rarely required). If you do go and have a plumber do it, have both the fill valve and flapper valve (and flush handle, if aluminum or brass and corroded) replaced at the same time, as all tend to go out with age - every 10 years or so. You don't want to have to call the plumber to replace another part in just a year or two.


From the sounds of it, you have a clog between the floor drain and the connection to the city sewer (unless you have a septic tank).  The lower flow rates of sinks / showers / dishwashers probable don't cause a backup like the washing machine does.  A couple of suggestions.

1.  Snake the drain line with a spade tip snake, twisting the snake as you advance it.  This should clear the partial blockage.

 2.  If feasable, have your washing machine discharge into a utility sink and put a strainer on the drain to catch the clothing fibre (fibres and grease from the sink probably made the clog in the first place not to mention a garbage disposal).

3.  Replace your floor drain with one that has a backflow preventer (looks like there is a ping pong ball in it).

 Good Luck

It is not uncommon for a plumber to have to go get the parts necessary to repair and complete the job.  It is very hard to determine what the problem is over the phone and it is not until the repair process begins that the parts needed to resolve the problem is discovered.  It may also depend on if the plumber is using hourly rates or per job rates.  I would hope the time to get the parts would be minimal and the charge would be as well!

You have not said how old your house is, what normal water line life in your area is, whether it is leaking under the foundation or under the yard, etc. Cost depends a great deal on length of run, depth to dig to get below frost line, whether excavation will be through trees or other obstructions or open area, whether ground along route is too steep for a backhoe to work on, etc.

The first thing you really need to figure out is whether this is a spot repair issue, or a total line replacement issue. Your plumber should be able to help with that determination.  Very general rule of thumb - very old line from before 80's, if galvanized pipe, could be at its practical life and be ready for total replacement. Copper line generally last about 50-70 years UNLESS in a corrosive soil environment or if it has groundwater flowing actively past it, then can be 20-30 years. Plastic lines from the 60's to 80's vary a lot - from as little as 10 years to 50 plus dependingon brand. Plastic lines (PVC, HDPE, PE) from the 80's and later are expected to last 50-100 years - most have not failed yet, so no good handle on how long they will last.

An above-ground or under the slab line a plumber will do. Buried line outside he generally subcontracts to an excavator to dig and backfill the line, or asks you to get the excavation done.


If section needing replacement is under your floor slab or foundation, then a full replacement can be many thousands of $ depending on how many linear feet, and if interior flooring will have to be replaced or if you are on a bare concrete slab or bringing the new line in above-ground once you get through the foundation. A simple one-spot buried pipe repair (based on acoustic locating and precisely measuring the location of the problem) can be as little as $400 but probably more often $1000 or so - more if poor access like under a slab underneath stairs.

If the runs to be replaced are exposed in a crawl space or basement than it can run as little as $20/LF (probably $400 minimum job cost) to replace.


Outside line to the street can run from as little as $10/LF in areas where the pipe is shallow (no annual frost penetration) and in easy digging soil, to $250/LF or more if deeply buried, have to excavate through trees and heavy roots or boulders, steep topography, other utility interferences etc. Generally not more than $50/LF. Commonly, instead of digging up the old line, they select a new semi-parallel route from a good connection point for you existing interior water lines at the foundation (maybe not where it currently comes in, depoending on access) to the street main shutoff valve (called a "key box", taking a route between them that is easiest to get a backhoe into and minimizes destruction of valuable plantings or trees. A number of $50/LF is commonly tossed around as "normal" for this type of job, if exceeding 100 feet or so and digging and access conditions are normal.

If your connection is in the middle of the street rather than along your side in the yard, that can easily add $2-5,000 to the job, as the water utility usually has to do that part, and repair the street afterwards. In a major throughway street, even more because of traffic control, multi-agency permits, etc.


As always, find 2-3 responsible, well-recommended (Anglie's List ?) contractors, and then get bids. The route I would go is first go with your regular plumber to locate the leak (probably acoustically, by listening for the leak) and determine the scope of work needed, then if major, go for multiple bids.