Is the slanted angle of the vertical pipe causing the leak under your sink, and should it be leveled for the correct fix?
Asked by Svetlana Damjanović 
7 months ago
Last Updated: May 15, 2024
Hey everyone, I’ve got a leak under my sink that just popped up out of nowhere. A couple of months back, I accidentally nudged the vertical pipe on the right side, but it slid back in and didn’t leak (I double-checked with paper towels for a week).
The right side is slightly angled upwards towards the left. Do you think this slant is causing the leak? The issue seems to be at the elbow, but I’m not sure if it’s above or below. I suspect it’s from the top since there’s nothing securing the vertical pipe in the elbow.
Any suggestions on how to fix this?
Just a heads up, I’m planning to redo the whole setup to make sure it’s done correctly. Thanks for all your help!
Consider using a continuous waste and eliminating that bs trap
What’s going on? Do you need a trap?
Needs a p trap instead. S traps are against the rules. Make sure to add a vent and put in a ptrap.
S traps are okay if they’re already in place. There’s nothing illegal about it.
Thumbs up
The “S” design in traps could create a water siphon, leading to water removal and allowing sewer gas to pass through. That’s why these traps are no longer permitted in plumbing codes and should be replaced if you have one. Just a heads up, you won’t get in trouble for having them, but they’re not up to code.
First off, the angle is clearly incorrect. It should tilt slightly downward towards the p-trap on the left. Regarding the leak, the nut on top of the elbow appears to be a compression fitting. It’s possible that it’s not tightened enough or was screwed in at a slight angle. To identify the source of the leak, dry it off and place paper towels around the elbow, observing closely to see where it becomes damp first. The solution will depend on the location of the leak.
Has an ‘s trap’.
Yep, my point remains valid.
Make sure there’s a tapered gasket inside the nut at the top of the elbow. If it came out easily, the downpipe may be too short or not fully inserted, the gasket could be dirty, or the nut might be loose. Also, the slope on the cross pipe should ideally be towards the J pipe
The horizontal seems to be leaning because the vertical on the right may not be seated properly in the elbow. Try loosening the nut and checking the washer
There should definitely be a gasket inside. Just tighten the wingnut a bit more
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The only issue with the pipe is that you are using two different schedules of PVC to plumb a double sink. Remember, water is lazy and won’t go uphill, so make sure to slope the pipes downward towards the drain. It doesn’t take much of an angle to ensure proper flow. I recommend starting fresh with schedule 40 PVC and a proper P trap.
The slope is incorrect
No ventilation
S is incorrect
Surprised it didn’t fail earlier
Has the best arrangement. This is exactly how I arranged mine and luckily I could also use a long sweep 90 on one side.
Let’s rethink and redo this – it seems like trouble is brewing.
Primer and cement.
My initial reaction is that the design seems a bit off. To start, the extensions from the sink are excessively long. The double back p trap is not needed. Here’s my line of thinking. The closer the elbows are to the sink, the less chance of a leak. Ignoring the force of falling water is risky. The hardware store offers a double sink setup as a single unit, with wide radius elbows connected directly to the sink drains with short extensions forming a T at the bottom, a single p-trap, and a sanitary elbow connecting to the drain. It’s a simpler setup with fewer pieces. The last one I purchased was priced under $20.00 USD.
Since no one has mentioned it directly, the likely culprit is the 1½” ferrule. Unscrew the nut, replace the probably broken ferrule, and reassemble everything properly. It should solve the issue. While a complete replacement is the ideal solution, as others have already advised.
The first step is figuring out where the leak is coming from. Then you can focus on that specific area. That right side should ideally be flat or slightly angled towards the drain. When water accumulates there, it’s never a good sign. It might be the source of the problem… or maybe not. Make sure there are clear plastic V washers in each fitting. If they’re missing, that’s definitely an issue. There could be multiple factors at play here. While the joints slide in quite smoothly, they shouldn’t easily slip out. Consider replacing those connections. Clear out everything underneath. Thoroughly dry and clean the area. Fill both sinks at least halfway. While underneath with a good flashlight, drain one sink and observe closely. Remember the details with blue tape or something similar. Repeat the process on the other side. Head to Home Depot and purchase all necessary items. You can always return what you don’t end up using. Replace any parts that are leaking (or just swap everything out if you prefer). Address the sagging pipe. Test everything again. Keep an eye on the situation for a week or longer.