Disclaimer, I have pulled all the permits, I already passed several inspections, my jurisdiction is happy to have the homeowner do their work.

I need to connect two underground PE gas lines downstream the meter pictured below that will go to a BBQ area and a detached garage:

Gas meter

This is the type of riser I will use to transition from the underground PE:

Gas riser

I plan to remove those two unnecessary 90 elbows and go straight into the dwelling so I will also have more space; however I am concerned I will not physically be able to connect all the fittings in the following way:

gas fittings

And that I will need to use the unions below:

gas fittings with unions

I have read multiple times unions are bad, they are guaranteed to leak, they should not be used. However I cannot find a way to make this work without them. I am not only trying to satisfy code but to implement a good solution. Is there any alternative?

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    No, and in fact, most of the best plumbers are union plumbers who know the rules down to the tee, wye do you ask? [jk]
    – dandavis
    Commented Oct 24, 2023 at 5:10
  • 2
    The two 90 degree corners provide flexibility for thermal expansion. I'm not sure if it is strictly necessary here, but it is something to consider before removing them.
    – jpa
    Commented Oct 24, 2023 at 6:21
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    @jpa the two 90s were introduced when they upgraded the gas meter with a taller one few months ago. Before that, it was a straight line. I need some added height and the line going into the house has a 90 elbow as soon as it crosses the wall, it's less than two feet long total, I think it's very interesting to take thermal expansion into account here but all things considered, I think I will proceed and go straight into the wall there. Commented Oct 24, 2023 at 16:06
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    I have obtained written certification from the fitting's manufacturer after training. The permit I pulled includes a visit from a city inspector that will want to see a pressure test and other visual checks. I grew up in Europe (and I worked as an Electrician) I am well aware of how it works there and I consider the way of my current jurisdiction in the US very just - the inspector will not use any leniency with me and will want to see a state of the art installation in any case. Commented Oct 24, 2023 at 22:10
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    According to Local Union 60, "Union membership will guarantee that you will have the greatest opportunity to become the finest craftsman available anywhere in the country. " That doesn't seem harmful to plumbing?
    – rrauenza
    Commented Oct 24, 2023 at 23:48

2 Answers 2


The IFGC doesn't allow unions in concealed spaces because of their leaking proneness. See the IFGC's 404.5 commentary. You're right to try avoiding their use, but you're not describing a concealed space.

There exist half-left-handed/half-right-handed threaded couplings that would allow you to tighten your risers without rotating them, e.g. https://www.plumbingsupply.com/leftright.html.

The unions are outdoors, though, so they're perfectly fine.

  • I have heard about the LR threads and yeah I guess they take more skill to install than a union but nothing crazy. I really did not understand the part about abandoning the risers. I can cut and thread my own pipe or have the store do it for me, that is surely not a problem, but how would I exactly transition to the PE pipe? Commented Oct 23, 2023 at 22:13
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    @Alessio Sangalli, the iron pipe is bad advice. There's an expensive, painful process to protect the pipe against corrosion. Totally not worth it.
    – popham
    Commented Oct 23, 2023 at 23:35
  • OK to clarify, you initially suggested to use regular fittings that can be screwed on without the need of a unions and then the use of: homedepot.com/p/ciao/312782718 to transition to PE underground. However you then realized there are complex corrosion issues to take into account when going underground with black iron pipes and fittings and that solution was then considered not worth it. Commented Oct 24, 2023 at 16:09

Unions are fine. You see them in plumbing work all the time. It's impossible to plumb some items without a union. What you want to avoid is unnecessary unions. If there's a way to plumb it with fewer unions that doesn't cause you undue headaches elsewhere, go for it. Otherwise you should use the union where you need the union. Just make sure the plumbing is well supported, well protected, and properly leak tested before being put in to service.

  • Thanks. The "well protected" is relevant here: the riser will be buried down below and supported by the sand and dirt itself. That could in principle, with time, extort forces on the fitting that are beyond my control over the initial setup. Also, I can pressure test the buried line, but once I connect it to the main gas line, the only way I have to "leak test" is to spray soapy water? Commented Oct 23, 2023 at 21:53
  • 2
    You might also be able to eliminate a bunch of connections by adding a manifold.
    – KMJ
    Commented Oct 23, 2023 at 22:11
  • I'm not familiar with manifolds, do you have a link? I see online some stuff for CSST systems Commented Oct 23, 2023 at 22:18
  • The PE and its last bend should be able to absorb any reasonable underground movement. If you also clamp the pipe to the wall around where it enters and all around that double tee none of the outside movement should impact it.
    – jay613
    Commented Oct 23, 2023 at 22:34
  • Agreed with the other comment that the two 90 degree bends are not necessarily unneeded - they might be absorbing movement of the meter relative to the house. I was thinking of something like this, though I'm not seeing anything for just two outlets: ferguson.com/product/…
    – KMJ
    Commented Oct 24, 2023 at 15:12

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