Settling Soil breaking underground water connections

[livens]

Hi,

I live in a newish development, around 8 years old. Many of my neighbors have had broken water connections due to the soil settling down. This weekend it finally happened to me I dug the hole, 3'x4' and 5' deep, fixed the connection and now Im concerned about filling it back in. My close neighbor has went through this twice, his re-setteled and broke the connection again. I wish to avoid 6 hours of backbreaking shovel work. Here is a simple diagram of what our connections look like:



The leaks Ive seen have always been at the PVC/Copper connection. The line was pushed down almost 5" in my case.

The second time around my neighbor filled sand in under and above his line. He's convinced the sand will flow around the pipe as the ground settles. Im not so sure.

So my question is: What is the best way to prevent ground settle from pushing the pipe down the stressing the connection?

Thanks,

Jeremy

 

[Bluebinky]

Don't have any magic advice about soil settling... IMHO (not a pro) sand is a good thing, but if the soil settles 5 inches, it probably won't help. Is it possible that some of the settling was due to the leak?

You might try extending the copper further away from the foundation to lessen the strain at the transition. How far does the copper pipe extend now?

Also, copper to PVC transitions are problematic -- female PVC threads tend to split open and male PVC threads break at the base of the threads. Google "pvc to brass transition" for fittings engineered for this purpose. They are expensive, but may help.

 

[Sponsor]

 

[JohnjH2o1]

Use a sch 80 PVC male instead of a sch 40 PVC male. It will take a little more stress.

John

 

[hj]

PVC "male adapters" regardless of the schedule are the most pathetic fittings in the industry. They can ALL snap when subjected to the least amount of stress. At times I have had to repair several of them in any given week, the last ones being a week ago. Use a sch. 80 threaded on one end nipple and a coupling, or the nipple and a "compression" coupling to give some flexibility, or a brass nipple and the compression coupling. DO NOT reuse a male adapter or you WILL be digging it up again someday.

 

[Spaceman Spiff]

What about sliding 6' of 4" PVC or SDR over the connection?

 

[Bluebinky]

Copper and PVC have vastly different thermal expansion coefficients. Plastic expands (and shrinks) something like twice as much as metal. This is why female PVC fittings over copper split open (they shrink around the metal). IMHO male threads do somewhat better (an obviously debatable subject), but since the thickness of the threaded section is limited they will break off -- just a matter of when. Use a compression fitting as hj said, or the engineered (reinforced) PVC to brass transition fittings (supply house or on-line, I haven't seen one in a big box store).

Of course, it would be even better dig it all up and run continuous copper (surrounded by sand) to the meter and be done with it...

 

[livens]

Wow, thanks for all of the replies!

bluebinky:

Ive got 2.5' of copper coming out of the concrete. I looked up those PVC/Brass engineered couplings, they look perfect for what I need.

johnjh2o1:

Ah, learn something new everyday! They did have the grey schd 80 pvc male fittings on them. I had thought the grey was just a different brand Probably just kept it from leaking sooner.

hj:

Ill be sure not to reuse any of the PVC fittings.

Spaceman:

Ill think about that. It would keep pressure off of the joint...


So I think Im going with the PVC to Brass Transition fitting. $30 isnt so bad for a more secure connection. But if this happens again Im going with bluebinky's suggestion of digging up allo f the PVC and laying copper out to the meter.

Also... because its such a tight place and I cannot move either side, PVC or copper, I could not get a replacement piece of PVC in using regular slip couplings. So I used a Expansion Coupling, one of those that telescopes out with o-rings inside. I was told by a seasoned plumber that the o-rings would last longer than me before shrinking and leaking... He was also a salesman so... Any thought on using these?

Thanks again,

Jeremy

 

[Bluebinky]

A couple more thoughts.

First -- I just realized that you are working 5 feet under ground. Be EXTREMELY careful -- if the soil gives way, you (your head) could be trapped underground! Sorry I didn't mention this earlier.

Also, I'm not claiming that the transition fitting is better than the compression fitting. It's something I recently discovered. That call is beyond me. HJ has been plumbing a long time (longer than me), and I would trust his advice more if there is any doubt...

Is there any way to use just one coupling? Fewer joints is better.

 

[hj]

I did NOT say to not reuse any of the fittings, I said "Do not use a NEW male adapter" to replace the broken one. The ONLY way I would repair it is with a brass nipple into a "compression" coupling. Which gives some protection agains stress and a thread that cannot break under ANY stress. I have seen the slip-fit devices break and/or leak. I do NOT like to fix something twice even if it is only 18" deep, much less five feet.

 

[Ballvalve]

I dont get you guys at all.

The only answer is soft copper with some loops in it so it can move with the earth, or a REAL stainless steel flex connector, or a swing joint made up of brass or SS street el's that can turn with the earth.

http://www.grainger.com/Grainger/HOSE-MASTER-Flexible-Metal-Hose-2ZV57?Pid=search

MUCH cheaper than a 5' hole.

Or just come into the house at a 90' loop [bend] like a "U" - You do not try and "fight" the earth with stronger fittings, you allow it to move the pipe a few nano inches a year.

 

[Bluebinky]

There are two issues here -- the earth moving and the transition between copper and PVC. Both may need to be addressed. I would shy away from SS underground, but otherwise agree.

 

[hj]

Ballvalve, you are trying to overcomplicate the repair. copper does NOT need loops, or expansion swing joints, or any of your other "solutions:.

 

[Cwhyu2]

I know what I post may or may not help you,but Cincinnati water works will not allow anything other than type K
soft copper,to connect to there curb stop. And if it is less than 100ft there cannot be any fittings from the curb
stop till inside the foundation wall and only one fitting before the meter tailpiece, and over 100ft must be
approved flare couplings.My feeling is your best bet is to replace now because you will have the same problem
again.Just my opinion.

 

[livens]

I know what I post may or may not help you,but Cincinnati water works will not allow anything other than type K
soft copper,to connect to there curb stop. And if it is less than 100ft there cannot be any fittings from the curb
stop till inside the foundation wall and only one fitting before the meter tailpiece, and over 100ft must be
approved flare couplings.My feeling is your best bet is to replace now because you will have the same problem
again.Just my opinion.

I WISH that was code around here. It would save us alot of trouble if they had to put copper all the way. But the PVC is so much cheaper for the builder, so Im sure it would be fought tooth and nail.

I didnt realize they made SS flex hose for this purpose. But I agree with bluebinky. Copper fitted to SS underground would cause a small electric charge to flow, eroding/corroding one side? Ive seen this happen above ground with copper to steel.

hj:

Ive seen the compression couplings but was under the impression that if the pipes became misaligned they would leak. I have serious reservations about burying it. And now Im worried about the expansion couplings too...

I was also advised I could dig the PVC back about 5' so I can raise it up enough, and the copper, to put a regular glued joint. I do risk pinching the copper, especially at the concrete, but was told it could handle this once.

And yep, I am leery of cave ins. I dug an outward taper to the walls, not straight up and down.

Thanks again, you all have given me much to think about.

 

[hj]

quote; was also advised I could dig the PVC back about 5' so I can raise it up enough, and the copper, to put a regular glued joint. I do risk pinching the copper, especially at the concrete, but was told it could handle this once.

The reason for using the compression joints, but the ones for ips pipes are NOT like the ones for copper. They have rubber gaskets and are designed TO ALLOW flexing. You can raise the PVC, but the copper will kink with the short length you have, and once it is kinked it will ALWAYS be kinked until it cracks at that point.

 

[BobL43]

I know what I post may or may not help you,but Cincinnati water works will not allow anything other than type K
soft copper,to connect to there curb stop. And if it is less than 100ft there cannot be any fittings from the curb
stop till inside the foundation wall and only one fitting before the meter tailpiece, and over 100ft must be
approved flare couplings.My feeling is your best bet is to replace now because you will have the same problem
again.Just my opinion.

Same here. I dug the trench by hand 6 feet deep from the street (50 feet) to my house, laid the L copper in the trench, through the concrete foundation wall, and the water company connected it to their meter and the new water main they installed in the streets in 1973.
We all had wells here before that.

 

[Ballvalve]

Also... because its such a tight place and I cannot move either side, PVC or copper, I could not get a replacement piece of PVC in using regular slip couplings. So I used a Expansion Coupling, one of those that telescopes out with o-rings inside. I was told by a seasoned plumber that the o-rings would last longer than me before shrinking and leaking... He was also a salesman so... Any thought on using these?

How long do the o-rings on your tractor and lawnmower last? Slip joints are for quick temporary repairs where you can go back to them.

Your soil, if I know soil, is settling DOWN, not laterally, so a slip joint has no meaning for this case whatsoever. It'll crack like a chinese dollar store toy.

You dont use engineered fittings to resist downward pressure, you build a flexible joint that can rotate laterally and ride with the motion.

Its not over working it - its the simplest and really only solution.

And if you dont rent a compactor to backfill, be sure to install a 6" tube so you can watch the pipe move again. The following applies to water service entrance as well.

Service Entrance. Gas piping entering the building must be protected from accidental damage by vehicles, foundation settlement or vibration. Where practical, the entrance should be above grade and provided with a self tightening swing joint prior to entering the building. Gas piping shall not be placed in unventilated spaces, such as trenches or unventilated shafts, where leaking gas could accumulate and explode

 

[livens]

ballvalve,

Im having trouble visualizing what a "self tightening swing joint" would look like. Could you elaborate on what this looks like?

Again I would like to thank everyone for these very enlightening posts. It seems the "plumbers" I have spoken with are content with a repair that will only last a few years.

 

[hj]

Gas piping is NOT the same as water pipes and that paragraph has absolutely NOTHING to do with the current subject. The "compression" couplings we are referring to do NOT use "O" rings for their seals, so a comparison with "automobile seals" is also irrelevent. They WILL absorb vertical movement, which is why I use them. I ONLY make repairs that last as long as possible. The original installers made a connection which woud last "for at least the year of their warranty responsibility". Once that was past they did not care whether it broke or not. It is almost impossible to make a "self tightening swing joint" because as soon as one joint moves to "tighten", an adjacent one MUST move in the opposite direction and "loosen".

 

[livens]

I think Ill just not use any of the repair connections, expansion or compression. Ill just dig the pvc back another 6' so I can have 2 sides of PVC that I can raise up and use a glued on slip coupling.