Thread: Insert Copper Pipe (Water main) into a PVC Pipe?

Is it a good idea to insert a copper main water line (from water meter to the house) into a Schedule 40 PVC pipe? Line would buried around 12 inches underground. Why or why not? Would inserting the copper pipe into a PVC pipe violate building code? Should the copper pipe be Type M or L and why? Thank you.

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I've heard of that being done. It isn't something that is done around here as a standard practice. Don't know about CA. As far as copper, neither M or L. We don't use copper pipe for mains, one uses copper roll, Type K (if I remember right). Continuous run from B-box to house, no solder joints.
I'm sure a CA inspector will chime in soon enough about local practices.

M is for HW heating system only, and should not be used for domestic water.

Originally Posted by K. Smith

Is it a good idea to insert a copper main water line (from water meter to the house) into a Schedule 40 PVC pipe?

Does not hurt anything as long as there is no intent to use that as a grounding electrode. Never heard of it being done, though.

Line would buried around 12 inches underground. Why or why not?

There are some instances where sleeving the pipe may even be required.

I suspect the only reason to do it would be for protection against physical damage.

Would inserting the copper pipe into a PVC pipe violate building code?

Only if the copper pipe was intended to be used as a grounding system grounding electrode, otherwise I can't think of any reason it would not be allowed.

You said "around 12 inches underground" ... what part of CA are you in? If you are in a part which is above the freeze line (above the 32 degree F design temperature line) then it would be required to be that far below the frost depth.

Originally Posted by Zibby Bujno

M is for HW heating system only, and should not be used for domestic water.

Nope. M is used for domestic water all the time. I do not know where you get your information. But I can tell you Chicago been using and allowed type M copper for many years. Mr. Keller is correct though underground water service is done in Type K copper and useally soft copper rolls. Solder joints are not allowed but silver brazed joints are allowed, but for repairs most areas require underground rated flare couplings.

In addition to being an inspector, I'm also a California plumbing contractor. (or was)
I'm a bit unclear about the term "insert". To me this means to slip something inside something else. That is NOT and acceptable connection anywhere that I'm aware of. Any kind of "slip" joint on a pressure line is not a great idea. I have seen double "compression" type unions used for repairs and they have to be strapped to hell to keep them together.

The copper should daylight at least 6 inches above ground and the acceptable connection would be a threaded adapter. Male PVC IPS fitting into female IPS fitting on the copper. Reversing the fitting setup creates "hoop stress" due to the tapered threads and will break/split the PVC.

As for depth, not much freeze or frost line issues in 90% of the state. Metal lines get buried 12 inches, plastic 18 inches.

Is the house plumbing copper or plastic? The reason I ask is that copper plumbing is grounded. If the water main is plastic, grounding the system has no effect except to the ground rods (and in my jurisdiction 2 are required). Typically we'll run the copper main out of the building 10 feet and then switch to plastic to the meter.

Originally Posted by K. Smith

Is it a good idea to insert a copper main water line (from water meter to the house) into a Schedule 40 PVC pipe? Line would buried around 12 inches underground. Why or why not? Would inserting the copper pipe into a PVC pipe violate building code? Should the copper pipe be Type M or L and why? Thank you.

Could the copper pipe in question be just sleeved in PVC where it goes through the foundation wall?

Originally Posted by James Duffin

Could the copper pipe in question be just sleeved in PVC where it goes through the foundation wall?

Yes, if the GC planned ahead to that extent. Usually the plumber will just come in with a concrete bore and cut a hole where he needs one. The installation is then finished off with an appropriate polymeric sealant and the exterior insulation and WRB repaired.

Originally Posted by Dana Bostick

In addition to being an inspector, I'm also a California plumbing contractor. (or was)
I'm a bit unclear about the term "insert". To me this means to slip something inside something else. That is NOT and acceptable connection anywhere that I'm aware of. Any kind of "slip" joint on a pressure line is not a great idea. I have seen double "compression" type unions used for repairs and they have to be strapped to hell to keep them together.

Dana,

The PVC is being used to "sleeve" the copper piping. I believe the terminology threw you off.

Originally Posted by James Duffin

Could the copper pipe in question be just sleeved in PVC where it goes through the foundation wall?

I those cases the sleeve is required to be two sizes larger than the pipe.

Originally Posted by James Risley

Seems like a very good idea with the supply only having 12 inches of cover. Will help with damaging digging with seasonal gardening. If soil contains sharp rocks or broken bricks etc from construction, then damage to water pipe (copper or otherwise) would be minimized. Also do this becasue pvc is extra cheap and if necessary replacement water supply couldd be pulled through pvc instead of digging up yard.

I sleeve PEX and schedule 80 PVC waterlines in schedule 40 PVC all of the time, especially when it runs underneath a concrete or asphalt driveway, porch, rockery or planter box.

A continuous 4" schedule 40 sleeve is cheap insurance against abrasions from backfill or other unforeseen factors -- And if the budget is padded enough, we'll run a second chase as an auxiliary/future.

Which actually came in handy earlier this week -- We've had some pretty fierce winds over the last few weeks, fierce enough to rock 200+ year old Douglas fir trees -- The rocking raised and broke the first 4" chase which sheered off the 2" schedule 80 waterline inside on a job we did back in 1999.

Fortunately, a camera sent down the auxiliary chase showed it to be undamaged -- So we dug up the waterline where it ran parallel to the driveway and fished a 20 foot length of 2" straight PEX through the auxiliary chase and reconnected it at both ends.

We were in and out in 6 hours and all of the digging was done by the homeowners landscapers, which saved them a bundle in labor and ensured that all of the landscaping was placed exactly where it was before the excavation.

Originally Posted by Eric Ramsing

Is the house plumbing copper or plastic? The reason I ask is that copper plumbing is grounded. If the water main is plastic, grounding the system has no effect except to the ground rods (and in my jurisdiction 2 are required). Typically we'll run the copper main out of the building 10 feet and then switch to plastic to the meter.

We do that most of the time as well if the interior is plumbed with copper, although we generally make the transition to PEX or schedule 80 PVC at the 6" mark, which seems to satisfy both the Plumbing Inspectors and the Electrical Inspectors.

Originally Posted by Zibby Bujno

M is for HW heating system only, and should not be used for domestic water.

Lots of M installed here in Texas for potable water supplies, I have also seen horizontal waste lines and AC condensate drains installed in M.

Further info from the Copper Development Assoc.

http://www.copper.org/applications/p..._concrete.html

Copper.org: Plumbing: TechCorner - How to Prevent Corrosion of Copper Tube in Underground or Buried Applications

It is almost always a good idea to use a sleeve to lower risk.

Type L is thicker and stronger than type M...also a little more costly but worth the $$ for something that will last 100 years.

We used type L in the 1970s for all domestic solar systems since the piping was exposed to extreme conditions.