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Pass PVC through a plastic lid without leaking Answered

I'm trying to pass a PVC pipe through a plastic lid into a plastic box without leaking water from the pipe or the box. The water in the pipe will be pressurized, while the water in the box will be splashed. A small leak isn't a big deal. Unfortunately, this is also a bit of a stress point, though not terribly.

See the picture and the diagram below (which is actually not quite right; the pipe on the top won't be that long; it will turn 90 degrees just above the plastic lid.

Any suggestions on how to keep it from leaking? Perhaps make the T under the lid flush with the lid and the same for the elbow joint above it, and then make the hole as small as possible? That wouldn't keep all water out though, but it may work for splashes.

Any ideas are greatly appreciated!




4 years ago

If you are using PVC pipe for plumbing, it should come in various standard sizes and have various fittings available to glue, clamp or screw on. The easiest thing to do is to cut a hole big enough for the pipe to go through and seal around with a good silicone caulk. It might be tough to get the right size rubber grommet. You can also end the pipe with a flange so you can screw it to the box top. The underside should have a similar size flange and rubber or vinyl washers/silicone caulk to seal when it is all nut and bolted together. Or cut a smaller hole for an inner pipe coupler to pass through the box. The larger diameter pipe on top and a short length on the inside will clamp to the boxtop for reinforcement and still caulk it up. Good luck.


Reply 4 years ago

Thanks for the quick reply! I think I'll try a flange and silicone. I've been looking for flanges, and most of the ones I've found are two pieces (see below). That confused me a little. Perhaps the idea is to slide the larger piece a ways onto the pipe, and then glue or melt the smaller piece onto the pipe, with the lip at the end of the pipe. Then you could slide the larger piece back and it wouldn't come off. That wouldn't make a seal though, and it doesn't seem it would glue well. Silicone caulk should fix it up fine, but I was just wondering if I misunderstood the intended use. I've searched but haven't found anywhere that covers this. And I guess it would have to be bolted with (PVC?) nuts and bolts, which would require a few more holes, which could be sealed with caulk. Thanks again!