I'm having trouble unclogging a kitchen sink pipe. I've taken apart everything outside the wall and cleaned it, but inspection showed that despite a bit of dirt, none of those parts are blocked. I have also snaked the pipe going into the wall and found no blockage. So whatever blocks it must be deep in the pipe, but I'm reasonably sure it is in that pipe because other sinks and the toilet on the same floor have no issues.

And yet, water goes out at a speed you barely notice when watching. Basically, drips. A half-filled sink drains in maybe half an hour, maybe even more. Sometimes it stops completely.

I've also used chemicals to no effect.

Then I've used the plunger, quite extensively. After working for quite a while, a white powdery substance started to come out of the pipe, with a consistency like flour or dough. Mostly very fine, but also some bigger parts (up to 1cm across) which was just the stuff clung together. It clings to everything and washes very badly from hands, etc. maybe some oil got mixed in.

Despite throwing out maybe a large cup full of it, the blockage remains. Continuing to use the plunger, the stuff keeps coming, but at low quantity. I believe this might be the blockage, but I have no idea how much remains and stopped after applying the plunger for maybe an hour.

I should mention that the dishwasher also empties into this pipe (it is connected just below the sink).

Is there anything else I can do or I am missing? Keeping on with the plunger might work, but who knows how many hours are needed. My current plan is to call a plumber and request they come with whatever special equipment they have. But maybe I'm just missing something else I didn't try yet?

additional information:

This is a detached house in Europe, with basement. So no crawlspace under the floor etc.

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    Is there a cleanout plug you can unscrew perhaps on the wall outside near the kitchen sink? If so, run some water with a hose into it and see if the blockage is beyond it or not. – Jim Stewart May 27 at 11:15
  • There's no cleanout plug visible anywhere. The pipe runs into the wall and then down. From what I can hear in the wall, it then runs the length of the house and probably joins the large pipe going into the basement where everything goes outside into the sewer. – Tom May 27 at 12:07
  • If there is no outside cleanout, then plumbers may run a snake down a roof vent. – Jim Stewart May 27 at 12:20
  • won't that run into the main pipe, no the connecting pipe from the sink? Everything else in the house runs, so I suspect the pipe connecting the kitchen sink to the main pipe(s). I doubt that is reachable from the roof vent. – Tom May 27 at 12:28
  • So in your case they would run the snake from the kitchen sink drain. You can buy manually operated snakes at the hardware store. – Jim Stewart May 27 at 13:01

You could try boiling water.

On the theory that the clingy white stuff is congealed grease which is blocking the pipe, you could boil a big pot of water and pour that down. The boiling water will have a long dwell time at the clog if it drains as slow as you say. Maybe enough to melt the grease and loosen the clog.

You could try lye.

Or if that is not available, ammonia or sodium carbonate (washing soda; also in automatic dishwasher detergent). These are alkaline and I suggest because maybe the "chemicals" you mentioned trying were acids. Again working on the theory that this is grease, alkaline chemicals will saponify the grease and make it soluble in water.

Once unblocked, find out who is pouring grease down your drain. And instruct them on their error, or it will happen again.

  • Grease. Yes, if there is a partial blockage somewhere, grease from pans and other cooking items might have collected there. We actually did try hot water, and in combination with more plunging it freed the pipe at least partially, water is going out now, though I still feel like it is not entirely unclogged (it could go faster). I'll accept this answer because that actually worked. – Tom May 28 at 5:27

Snaking should be the answer, but if all else fails then you may want to try one of these fun gadgets:

Kleer Drain 100 Instant Drain Opener

I have used this successfully on my main drain. The trick is you want to block as many alternate places for the air to go as you can so that the pressure goes down the drain rather than out to other fixtures.

  • This is very interesting. I didn't even know this exists, and it's not expensive. Can you elaborate in 2 or 3 sentences on how it works? It's not clear from the amazon link except that it creates air pressure. – Tom May 27 at 15:29
  • The cartridges are filled with compress CO2 (carbon dioxide) - similar to cartridges used for air guns. The plunger covers the drain opening so that when you press it down it pops the cartridge open and the CO2 goes down the drain very quickly. That is often (no guarantee...) enough to break up the blockage. – manassehkatz May 27 at 15:37
  • Thanks. I didn't yet try this but I'll keep an eye out for these in the hardware store. Probably a good thing to simply have at home. – Tom May 28 at 5:28

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