Just moved to my newly renovated home. I found those pipes looks a bit weird.

The first photo is the kitchen sink drain pipe, the p type pipe tiled a lot, will this causing any potential clog problem?


The second photo is the radiator pipe, I feel they are all pushing each other and bent, is the a risk for leaking?

Radiator pipe

I am a completely noob in plumbing, maybe I am asking non-sense.

  • 1
    Usually want smooth solid pipes for drains to make it harder for clogs catch on the insides. Plastic pipes are hard to be perfectly straight, usually come/shipped in coils, but should be placed not in forced positions. A good plumber would probably use another elbow, to go around that inlet pipe, but I would wait to see if a leak develops.
    – crip659
    Apr 21, 2022 at 12:49
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    I installed CPVC supply lines similar to your 2nd picture in my house more than 25 years ago. They're not straight, until recently, they weren't well supported, and I've never had a drip of water come out of any of the fittings. It's not high quality workmanship that I'm proud of, but it certainly works.
    – FreeMan
    Apr 21, 2022 at 13:44
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    I don't like those right angle bends at the bottom of the grey drain lines.
    – SteveSh
    Apr 21, 2022 at 15:49
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    I agree, @SteveSh, but this seems to be common outside the US. Looks so wrong to my eyes, but I've seen lots of pics here with similar set ups...
    – FreeMan
    Apr 21, 2022 at 17:59
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    As mentioned by Machavity in his answer, the red line in your drawing is an S-trap and a corrugated hose is used to connnect to the drainpipe in the wall. Both are plumbing code violations. As to your question, that corrugated hose at the bottom has a high potential for creating a clog. The good news is that the plug at the bottom with the yellow handle and the corrugated hose appears to removable making it easy to fix any clog issue. I would guess that the S-trap is the biggest issue, with the possibility of draining the water out of the trap. Apr 21, 2022 at 22:43

1 Answer 1


Yeah that's... really odd. Instead of a P-trap you've got something closer to an S-trap there.

The first thing to check on this would be slope. From the drain in the picture, you need about 1/4" (about 6mm) slope. It's hard to tell if that pipe slopes at all.

As to the drain clogging, someone realized this is a janky setup and at least did one thing smart: it looks like there's a cleanout at the bottom of the trap. A normal P-trap is designed to catch as little sediment inside as possible. This weird S-trap will catch a ton of sediment because the water has to turn 90 degrees at first (so you lose any gravity-assisted momentum), flow down the trap, then back up almost the same distance before hitting the drain line. Anything solid is likely to get caught there. You'll have to open the cleanout on a regular basis to make sure it doesn't get clogged (and it will be full of water which will make a mess, and it's up against the wall, which is probably drywall, making it worse).

If I had to guess, I'd say this setup was designed to maximize under-sink space at the cost of drain flow. If there's any way to replace this with a normal P-trap, I would do so.

The good news on the bottom picture is you're using what looks to be flexible plastic pipe. I don't see any extreme forces on the pipe so I wouldn't worry about it.

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