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Very Slow Bathroom Sink Drain

Ok, I'm at a complete loss on this one. I have a bathroom sink on the first floor of my home that has a clog deep in a pipe somewhere. The house has cast iron waste pipes throughout.

Anyway, I can run the water and it appears to drain but after 10-15 seconds, it starts backing up. I've tried plunging it, snaking it (with a 25 foot hand snake and a 25 foot, 5/16 inch power snake) and no matter what I do, it's still draining slow. The pipes don't have that far to go before they reach the main sewage line (maybe 15 feet total so the 25 foot snake is plenty). I obviously can't see behind the wall but from what I see in the basement, this pipe drops right down through the basement ceiling, runs along it, and then meets up with the main sewage line. So I'm pretty sure it's a dedicated waste line from sink to main sewage line. Everything else in the house drains perfectly fine, it's just this one sink.

I thought that maybe the bathroom sink (directly above this one on the 2nd floor) share the same drainage pipe but I don't think it does. I ran the sink upstairs for a good 2-3 minutes this morning to see if the sink downstairs would back up. It didn't.

I'm thinking of having someone come in to snake or fix it but I don't want to spend a couple hundred bucks. I could replace the waste pipe with PVC for a lot less.

Anyone have any ideas? This thing has me incredibly frustrated!

Thanks in advance,


Re: Very Slow Bathroom Sink Drain

If you are willing and able to replace the pipe with PVC, you will never be sorry. And it will cost you less than one visit from the rooter guy, as you know.

Re: Very Slow Bathroom Sink Drain

Where are you snaking it from? If the line is 15' and your getting 25' of snake in the line without clearing it the snake may be going up the vent line.


Re: Very Slow Bathroom Sink Drain

I'm snaking the line from the pipe coming out of the wall (below the sink). I don't think the snake went up the vent. Each time I snaked it, I was able to shine a light into the pipe and see the snake was going down (I assume into the rest of the pipe) and not up (into the vent). Unless there's some funky stuff going on below, I'm pretty sure I was going where I needed to be.

Re: Very Slow Bathroom Sink Drain

I had a simillsr problem many years ago with galvanized and castiron. I was able to run a snake through and water would drain, for a short while. I finally found the problem was where the lines joined. Someone, either from inexperiance or to save a few bucks, brought the two lines together and used mortar to seal the joint. It had broken and restricted the flow. I replaced it with PVC and a distrobution box. That ended the problem

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