PVC water supply line vs copper

[PandaBear]

Got a slow leak in the water supply line, it leaked about 10 CCF in 2 months (based on my water bill) and I see a puddle in the middle of my front yard where the water line is coming in from.

Previously there was a bigger leak and we found / patch it. The line is about 100 ft and most of it is under a concrete driveway. A underground line plumber told me PVC (schedule 40) is very prone to crack when they age (house build in 1994) and say if I want to replace I should use copper line.

Cost to fix the leak (replace section of PVC) $500-600
Cost to repipe to copper, going through front yard of neighbor instead of under concrete driveway $4500-5000.

I am not too concern about the cost but, I do not see a lot of people complaining about PVC water line on the internet, and the only one I see is about hot water and over pressure. On the other hand I do see people mentioning soil acidity may be a problem with copper line instead. On the other hand my tree stump removal guy said schedule 40 is very weak and no one use it anymore, and they all switched to schedule 80 now.

So, am i understanding correctly that PVC should last and copper may corrode (according to what I see it has a lifespan of 40-50 years), or PVC will crack underground and copper is more durable?

The house is behind another house and far away from the meter, hence the cost. If it is right next to the water meter a copper line replacement would have been around $2400.

 

[Jimzz]

Neither... Use PEX. Cheap like cPVC but holds up well.

I replaced my main water line with a single 1" PEX run. Been 5 years and still great.

 

[PandaBear]

Is there something that will last 75 years when buried underground?

 

[Jimzz]

Originally Posted by PandaBear
Is there something that will last 75 years when buried underground?



My main copper line only lasted 30 years then another 20 after being repaired from what I found in my house. Average life span of PEX is 50+ years so that is why I ran it in my house. Thats as long as its not exposed to UV light. PEX-A will last longest with B a close 2nd and C I don;t use.

 

[Rolla07]

Id stick with sched 40. I assumed my pool lines would of sprung a leak by now with the temperature swings and being underground but still no issues.

 

[walterjay]

Heavy duty black polyetheylene will go 75 years. I see non heavy duty poly installed in the 60's still going strong. It is also used on geothermal loop systems and has a very long life expectancy. Pex will also probably do well but it does not have a long term underground track record.

 

[doitmyself]

Yep, this (polyethylene) is what is most common for underground water supply in Michigan. It comes in numerous pressure grades (wall thickness). I have seen the cheap stuff get leaks from rubbing against stones in the backfill.

https://www.homedepot.com/b/Plumbin...ipe-Fittings/500-ft/N-5yc1vZbuu4Z1z115ip

 

[tom slick]

300' of 38 year old PVC main, no issues at my house.

 

[jhellwig]

I am amazed anyone would want to bury metal water pipe anymore especially in an earthquake prone state unless it was soft copper.

 

[WhyMe]

the pvc at moms house sprung a leak at 40 years old last year. instead of patching it up it was decided to run a new line. was repalced with pex. about 150 feet cost about $5k in the city of Seattle . they did it trenchless with a special machine that can go under slabs etc with no issues

these guys did . basically the same way

https://www.youtube.com/watch?v=v6dkP0oxa0I

 

[PimTac]

I agree with using PEX. Also make sure the line is buried with a layer of sand below and above, no rocks.

 

[StevieC]

I have Pex all throughout the house that we put in when we moved in because the copper that was in this 70 year old house was in bad shape. I would advocate for this. I'm using the black internal with the white outer jacket stuff.

I know my water main outside the house is going to go any time now with it also being super old so I bought insurance for this because it would be $5K to replace from what my neighbours tell me who have had it done.

If you do go copper route make sure they use the better grade. There is "M" and "L" grade copper with "L" being a thicker sturdier wall that will take longer to wear down. It's more costly but for hard to fix areas or commercial setup's or where circulation pumps are used "L" grade is the best to use if not using Pex. It's also far less likely to develop pinhole leaks over time which can drive your water bill up sky high if this happens underground and you can't see it.

Good luck

 

[bubbatime]

A plumber recommending copper, TODAY??!! What the heck??!! That would be flat out absurd, and incompetent down here, as I understand it. No one uses copper here. PEX is where its at. Easy to use, easy to fix, durable.

 

[PandaBear]

Actually, I asked 2 plumbers and they both say copper. My gut feeling says it has to do with fewer root related damage and people not living in the same house for more than 20 years.

The current pvc probably got damaged because of the trees they put in the front for decoration, the developer sold the house and knowing that it would be the 2nd or 3rd owners having to deal with a cherry root crushing the pvc.

 

[BMWTurboDzl]

Just make sure they use the correct thickness of copper pipe. Btw..if you still opt for PEX (PEX-b) you may want to make sure that the plumber uses the fittings recommended by the manufacturer otherwise you're more likely to develop leaks.

 

[Papa Bear]

Originally Posted by PandaBear
Is there something that will last 75 years when buried underground?


Yes, old galvanized will last 75 yrs.
I am old enough to see that the "plastic du jour" (newest, greatest thing since sliced bread) will be the thing that needs to be retrofitted in 10-20 yrs - either the pipe or the fittings.

 

[bmwpowere36m3]

PE... in our area all new utilities (water and gas) are run with it. Inside the home a mix of PEX and copper.

 

[Jimzz]

Originally Posted by Papa Bear
Originally Posted by PandaBear
Is there something that will last 75 years when buried underground?


Yes, old galvanized will last 75 yrs.
I am old enough to see that the "plastic du jour" (newest, greatest thing since sliced bread) will be the thing that needs to be retrofitted in 10-20 yrs - either the pipe or the fittings.


I had to cut ALL the galvanized pipe out of a house I flipped. What was not leaking was clogged up from rust. Theres a reason no one uses it expect some drop drain lines for noise reasons in thinner walls.

PEX is about 70 years old and all known issues are just that, known. As long as you keep it out of UV light it works fine.

cPVC is not to bad but the negatives out way the pros when comparing top PEX. So I don;t use it at all.

 

[PandaBear]

I dug it down and found a total of at least 3 compression couplings (2 seen here, 1 more on the left buried from the last fix),1 of them is leaking slowly (drip if I let it, but a small stream if I push on it). Looks like this line has been patched up a few times and 3 compression couplings are just too many on a short line. The leak is at the white coupling on both the left and the right side. Dripping about 1 drop per second if I don't apply any pressure on it.

Thinking about replacing the whole line from a 90 deg on the left to a 90 deg on the right, eliminating any buried compression coupling. A plumber said I still shouldn't use schedule 40 as they won't last, but use plastic coated copper tubing instead.

 

[Stelth]

Out here in California, copper is still king. I guess we don't commonly have acidic water or dirt. I also haven't heard of a lot of problems with Sch. 40 PVC water services. My own house was built some time between 1970-1972, and has a Type L soft copper water service. I would imagine the exterior of the pipe is like new, and the interior has a thin calcium coating, since I've dug up numerous old water services and found exactly that. I've been a plumber in San Diego County for 34 years, and it's obvious that our conditions here are different than much of the country. Pex and CPVC are of course popular for new construction, but California has been very conservative (say what?) when it comes to adopting plastics, especially after the Qest/polybutylene debacle.

If I lived in an area with soil chemistry that is corrosive to copper, I wouldn't use copper. OTOH, with soils that are friendly to copper, a Type K soft copper service should last several lifetimes.

I think that others here have more experience with the array of available plastics, so I won't give advice on those. I definitely agree with sand bedding, and keep in mind that any pipe can be sleeved as well.