I need to repair a severed 1 1/2" PVC drain line.


I have a Fernco flexible PVC coupling laying around, and I figured it will be much easier to use the flexible coupling instead of a rigid coupling.

Fernco flexible PVC coupling

I've searched Fernco's web site, but I was not able to determine if this fitting is rated for direct burial.

This is my plan for the repair:

The Plan

  • I think the clamps may suffer underground, but if you use some neoprene tape (ice & water shield etc.) on the joints I'm sure it will last indefinitely. There is no pressure, so any fairly rust resistant coupling should work fine. Apr 26 '13 at 11:45
  • I've seen lots of plumbers bury these when fixing sewer lines - connecting PVC to clay or cast iron. Not sure if its "correct" though.
    – Steven
    Apr 26 '13 at 13:07
  • 1
    I'd find out who owns that utility line running across and make them pay for the repair. Apr 26 '13 at 19:51
  • @ChrisCudmore The repair cost ~$8.00. I called 811 (dig safe), and nobody claimed the line.
    – Tester101
    Apr 27 '13 at 12:52

I just replaced the main stack in my house. Went from cast iron to pvc. I dug out about 10 foot in my basement to connect the pvc to the clay piping that goes out to my front yard.

I used a bigger version of this coupling to marry the pvc to the clay and it is buried underground and under concrete.

Inspector told me that they only start allowing these underground a few years ago in my area. He also told me to go get a thick trash bag and he came back with some rubber-band like material. He had me wrap the coupling with the trash bag and seal the bag with his wraps. He said the 20 cents and 5 minutes should keep it from rusting out an extra 20 years.

  • So I guess a complete answer would be that these are rated to use underground but whether they will pass local code is based on area. My area is very very strict with sewage/plumbing so I would assume that it would pass in most areas of US/Canada.
    – DMoore
    Apr 26 '13 at 22:04

Since I don't have a copy of Uniform Plumbing Code (UPC), I began by browsing through International Residential Code (IRC). I came across section 3303, which says:

2012 International Residential Code (IRC)


P3303.1.4 Piping. Discharge piping shall meet the requirements of Sections P3002.1, P3002.2, P3002.3 and P3003. Discharge piping shall include an accessible full flow check valve. Pipe and fittings shall be the same size as, or larger than, pump discharge tapping.

This pointed me to section 3003, where I found this...

2012 International Residential Code (IRC)


P3003.14 PVC plastic.
P3003.14.1 Mechanical joints. Mechanical joints on drainage pipe shall be made with an elastomeric seal conforming to ASTM C 1173, ASTM D 3212 or CSA B602. Mechanical joints shall not be installed in above-ground systems, unless otherwise approved. Joints shall be installed in accordance with the manufacturer's installation instructions.

After checking the manufacturers website, it turns out the fittings conform to ASTM C 1173.

ASTM C 1173

Flexible Transition Couplings for Underground Piping Systems

1.1 These specifications describe the properties of devices or assemblies suitable for use as flexible transition couplings, hereinafter referred to as couplings, for underground drainage and sewer piping systems.

So as it turns out, these fittings are indeed rated for direct burial.

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