Loud draining + dripping sound from basement sink

[shansen81]

Hi everyone,

My wife and I purchased a home a few months ago and there's a finished basement with a bathroom.

When we run the bathroom sink it seems to drain just fine while the water is running. After the water stops it makes a loud gurgling noise which is then followed by a dripping sound for several minutes. When I look down the drain I don't see anything dripping and it appears that there's an air pocket pushing itself up through the water and making the sound.

Here's a video: [ame]https://www.youtube.com/watch?v=9IB7Lfjjdz4[/ame]

I'll be completely honest that I don't really know the first thing about plumbing. Do you suppose this issue could be caused by a clog in the line? Would it be worth disassembling the p-trap to see if it's gummed up with hair, soap, toothpaste, etc.?

We know that if it's a clog then it's not in the main outside sewage line to the septic tank since we had a new pipe installed earlier this week (long story on that one).

Thanks everyone!

Scott

 

[Mr_David]

Good possibility that they did not vent the drain and it siphons the water out if the trap when it drains

 

[shansen81]

Thanks Mr. David! That would be what I suspected based on some things I've read. The water doesn't appear to leave the trap though and we haven't noticed any sewer smells so that's a good thing. This sink and toilet were draining to a second septic tank that we discovered a couple of weeks ago which is infested with roots and almost full. We have since installed a new sewage line so everything goes to the main septic tank that's been freshly emptied and cleaned of roots.

Back to the lack of a vent.. is this something that we should be concerned about? I couldn't tell you when the bathroom was done (probably in the 80's). The bathroom was put in because previous owners anticipated in laws living in the finished basement by the bathroom.

Here are a couple pictures - the top one is the sink. The trap goes into the wall against the vanity and then elbows at some point and goes along the wall to the right. The pipe then travels behind that wall and comes out behind it in the unfinished closet next to the bathroom. The PVC pipe from the sink attaches to a metal pipe which has another trap and then it goes into the ground where it meets up with the same sewage line that the basement toilet and upstairs kitchen sink and diswhasher connect to which leads to the septic.

Is there still a possibility that there might be a clog in that second trap before it goes into the floor? Or do you still think we're looking at a non-vented sink? We do have a vent that pops out of the roof and we haven't experienced this issue with any other plumbing fixtures in the house. The basement toilet flushes fine.

 

[Mr_David]

If it is trapped at the sink get rid of the second trap
How far is the 2nd one from the sink? less than 5 ft add a AAV.

 

[shansen81]

It is further than 5'. It's probably closer to 7'-8'.

Do you think air caught between the two traps could be what's causing this?