Our basement rough in for the shower drain has it located right where we want it, but it has no p-trap installed yet. I am unsure what I can do to add the p-trap but keep its location. I'm trying to avoid chewing up concrete, digging down and re-doing anything with it tying into the main drain line. I don't think moving the final drain closer to the wall is feasible and moving it further from the wall is undesirable aesthetically, though technically possible.

I don't have a picture, but I have drawn up what I'm basically working with, if it is helpful. The shower is framed to about 5'x7'. The current drain is located about 4 inches from the wall with the shower head on it (installing a linear shower drain). When the basement floor was poured, a cut out in the concrete floor was left approximately 12"x12", offset as shown. That hole/cutout leaves access to the gravel/stone underneath and the drain line. I can pull out the gravel to access where the drain ties into the main drain line, which is little more than a foot down from the concrete floor surface. I'm just not sure how to add a p-trap to this drain and keep its same location.

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I appreciate any ideas or suggestions anyone has.

  • I would suggest excavating to expose the drain line connection and taking then editing in a picture, for best insight into how to solve this. Details of that connection are going to matter in how to solve it correctly.
    – Ecnerwal
    Feb 7, 2023 at 16:24

1 Answer 1


Without an actual picture for confirmation, it's hard to be sure, but with a p-trap (which can be adjusted to drain many different ways), a couple of elbows (which can be had anywhere from a 22.5° to 90° bend) and a little bit of pipe, you should be able to aim the p-trap in a direction that will allow you to eventually line it up with the entrance to the drain line.

As with all DIY plumbing projects[1], it will be a matter of trial and error to determine which direction to aim the trap arm, then which fittings will be necessary to bend things around. Don't bypass the "street" fittings which don't require any pipe to allow one elbow to slip directly into another, allowing for tighter, space saving bends. This will be one more tool in your arsenal to find the right configuration.

I'd buy at least 2 of every elbow bend (in the pipe diameter you're using - 2" I'd guess) they sell at your favorite local store and a piece of pipe[2] and fiddle until you've got a layout that'll work[3]. When you're done, take the rest of the fittings back to the store and get your money back for those. It's a lot easier to do that than to have to keep running to the store for just one more elbow ought to do it...

[1] I'm quite certain that with training and a few years of experience, a professional plumber would look at it and "just know" what she needs, but we're not pros here...

[2] I'd recommend buying "full size" 10' sections not the "convenience" 2' or 5' sections they sell at the big box store. I was just looking at some last night. It was $20 for a 10' stick, $17 for a 5' stick and $12 for a 2' stick. You're going to have to cut it no matter what length you bring it home in, so you may as well spend the extra money saved on a hack saw of some sort to cut the pipe. Besides, if you're putting in a shower, you're probably putting in a sink and you can use some of the pipe for the sink drain.

[3] You should have a pretty short run from the start of the trap arm to where you reach the pipe currently in the ground, but make sure you maintain your 1/4" per foot slope to ensure good drainage and whatever you do, do not allow the pipe to go back up. You don't need two traps in a row...

  • Thanks, you may be right that just buying pieces and playing around with them may provide a quick solution. I guess I'm just not sure what rules are on p-traps... ie, can they be a loop as opposed to how they are normally installed. I have already completed the rest of the rough plumbing so I have plenty of pipe to play with. Just need fittings. I am unsure what you mean when you say "do not allow the pipe to go back up". Do you mean don't let it end up higher than I start with (or high enough to cause slope problems)? Feb 7, 2023 at 16:55
  • ... three of each elbow bend.. :-)
    – JACK
    Feb 7, 2023 at 17:32
  • You must maintain pitch, @JosephWhite, from the top of the trap arm down to the drain stub-out. Anywhere that the pipe goes back up will cause water to pool in the pipe and not drain properly. Not sure exactly what you mean by a "loop", but you could get your pieces dry-fitted in a way that you think works, then ask another question to ensure you're on the right track with what you've designed before you glue it up and have it inspected.
    – FreeMan
    Feb 7, 2023 at 17:41

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