Sink drain is slightly misaligned relative to trap

drainplumbingsink

The drain under the bottom of my sink, and the upwards section of the trap that is supposed to meet it, are misaligned—but by much less than other examples I can find online, including here. Looks to be about a quarter-inch off from a perfect fit. I’m hoping that this means there’s an easier way to fix it than getting new pipe and rerouting.

The “solution” apparently used by the contractors the previous owner hired was to jam a small section of pipe—a T for connecting the dishwasher drainage—in at an angle. This works poorly and produces a slow leak—that occasionally becomes a fast leak if the T section slips out of position, which happens every now and then.

Here’s what that looks like at the best of times:

sink drain into a T that is angled to try to meet misaligned trap

The T section there barely covers the gap—the overlap between the T section and the pipes above and below is about a sixteenth of an inch.

Here’s what it looks like if I disconnect the T section from the sink drain, and let it come straight out of the trap:

same sink drain with T straight out of trap, offset from sink drain

There is a little bit of wiggle in the pipe with the trap, so it can get a little closer than this, but not much; certainly not enough to close the gap at a straight shot. And anyway it won’t stay like that; it’ll just sag back down and the T section will slide out of place and dump water on the floor.

Notably, neither of these two connections are threaded. The T section and the trap each have a collar you can tighten (and tightening either too much cause the pipe it’s supposed to be clamping onto to instead pop out).

So the question is, what is the easiest way to solve this myself? Is there any way I can solve this myself? A “solution” being one that keeps water inside the pipe. Currently I can keep most of the water inside the pipe, but inevitably a little leaks out.

Various ideas I’ve had, that I don’t know enough to judge the merits of:

  • I know PTFE tape is mostly for threads, so I don’t think it’s appropriate at these joins, but is there something I can put in there?

  • Or wrap around it? I don’t love the sound of that since I’d worry water would collect in there but open to being corrected on that concern.

  • Or—much better—is there exist anything I could buy to actually have a proper seal at this kind of angle?

  • I note that there are threads on the pipe coming out of the sink itself—is any of that adjustable?

  • Or any way to move the trap that little bit closer to the wall? I suppose ultimately I could replace that pipe with a slightly shorter one, though I’m not sure I’d even know how to pick out the right one.

I’m fairly handy, but know little about plumbing. I don’t even know what here is something I might be able to successfully fix, and what should be left to professionals. I also live in a small apartment with limited workspace, and somewhat limited tools—pliers, wrenches, hammers, screwdrivers, levels, measuring tape, that sort of stuff, plus a power drill and a Dremel.

Finally, this is what the rest of the piping looks like, in case there’s anything relevant back there:

another angle under the sink, showing the rest of the pipe the trap connects to

As requested, more images of the black pipe in the back. Also visible are the drain hoses from the dishwasher. The black pipe comes out of the wall to the left of the sink, and elbows down to the vertical segment seen previously, and then elbows into the wall behind the sink.

further back under the sink, showing the bottom of the vertical pipe elbowing into the wall

upward-looking shot under the sink, how the “vertical” pipe comes horizontally out of the wall to the left before elbowing down to be vertical

The left of this photo is another wall, so this pipe is coming out of the wall there above the wood seen in the upper-left of the photo.

Best Answer

The evident minimal approach if you're in some backwards jurisdiction that requires metal drain pipes (as approved by the city council, that has been well-bribed by the plumber's union, say) is a slightly shorter threaded nipple from the Tee to the Trap. Looks like it's otherwise lined up OK, just too long. A competent, properly equipped plumber could cut it shorter and rethread it for you. Usually it's less expensive to just buy a new one the correct length, though.

The modern approach is a much shorter threaded nipple and a sliding trap adapter (female.) That will need a new trap with a slip joint output (male), or an adapter I can't recall ever seeing from the female pipe threaded trap outlet to a male slip joint. These can be had in metal if your LAHJ requires it, but the polypropylene plastic versions last longer (they don't corrode.) The new trap would ideally be of the sort with a union joint in the middle of the trap that allows for an additional degree of freedom in meeting the sink output. The slip joint can be made shorter or longer, and the union joint can be rotated. Everything gets lined up nicely, and then you tighten the union nut and the slip joint nut.

If you have to replace that trap, be sure to take the old one to the scrap yard, not the dumpster. There's money in that bronze.

A hack job approach that may or may not meet local code would be to cut a section from the middle of the threaded nipple and join it with a rubber coupling (no new threads required) to make it shorter, and slightly adjustable. Since I see two shielded (stainless steel outside reinforcing) rubber couplings at the tee, that evidently either meets local code, or the hack job done to leave you with this mess was never inspected (it certainly should not have passed if it had been.) So you'd get a suitably sized shielded rubber coupling, take a hacksaw to the pipe, then saw it off again to make it shorter, file the cut ends to remove sharp edges, and join them with the rubber coupling.

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