Slow Tub Drain on new bath install

Hi,

Having an issue with a new bathtub installed - the drain is extremely slow.

Unfortunately, I don't have any pictures to share, but I've attached an accurate illustration found on the web. It's a standard 4pc bathroom.

When we renovated, we did complete gut and installed new fixtures all around. We replaced the water supply lines with new pex and they're working great.

We left the original drain/vent lines intact, they are as illustrated. Those drain lines for the tub and vanity are the correct 1½" diameter and they exit into the vertical 3" main vent/soil stack, which is all up to local code (Ontario).

Problem:

When we fill the tub and open the drain, the water seems to just sit there. The drain is monumentally slow, but it does eventually seep out on it's own.

The vanity drains just fine, although there is now a gurgling that can be heard from the drain/overflow of the tub that wasn't there in the old bathroom.

No issues with the toilet.

What I've done:

- Checked for clogs - snaked the drain to the stack, no issues. Although I'm looking to get a better snake in there and really give it a good clearing. During the reno, we were careful to keep the drains properly covered and kept them clean and free of drywall compound/thinset/junk like that.

- Swore


Is it possible that the drain line slope is wrong and I've lost the siphoning action at the main stack? Those original lines were secured and did not move during the reno. But maybe the new tub drain is low enough to negatively affect the slope?

How likely is it that it's a clogged vent/stack? Again, vent lines are original, didn't move them, they worked fine before. Vanity seems to vent fine, but the gurgling suggests that maybe it's taking it's venting from the bathtub overflow/drain...

Any thoughts or suggestions would be appreciated.

First off, to House Repair Talk!

You didn't by chance leave a rag or something in the drain did ya?

HOW, did you snake the line?

your ptrap is most likely full of hair and gunk

couple of things you can do, remove the overflow cover, pull the linkage out and clean it

then,

they make a kitchen sink rubber flat stopper

hold the stopper over the over flow opening while you plunge the drain with a plunger
make sure your tub has a minimum of 3'' of water in it for the plunger to work correctly

try these steps, and if it does not clear, post back we can try something else

Hi all, thanks for the welcome Apologies for not being more thorough in the OP.

I definitely didn't leave a rag in there as I had to glue new abs tub drain kit and new p trap to the existing drain. All drains were cleaned with a rag, visually inspected and vacuumed out thoroughly before any installation was done to them.

The old tub didn't have any kind of trap on it when we took it out (definitely not code in my neck of the woods). I cut the drain from the old tub just after the connection from the tub drain kit to the drain line leading back to the stack.

So - new P Trap on there, definitely not clogged at that point.

As for snaking - I used a cheap, 15' x ¼" manual "drain auger" with not much of an open-wound boring head on it. Snaked it all the way back to the stack (wasn't far, 8' - 10'). I'm thinking of renting a better cleaning tool to make sure the line really is clear.

Are you sure the drain stop is adjusted to fully open?

Absolutely. We've installed a push-pull type plug, not much adjustment on it as it only has 2 positions - opened or closed. Nothing fancy.

The draining issue occurs with the stopper in the UP position (open drain). It's clearly open, you can see inside to the drain, everything at that point is unobstructed.

Sounds to me, who is not an expert, that you have a bad vent. That's the only way to explain the gurgle from the tub. You didn't hear it with the old drain bc there wasn't a pea trap to hold water and gurgle

Are you Absoultly sure there isn't another trap somewhere, sounfs like a double trap...just my 2 cents...

I'm entirely, 100% certain that there is no double trap on that line. We had the entire plumbing system in that room, including where it ties into the stack (stack is in wall right behind the toilet), out in the open where we could see everything.

There was no trap on that tub before the reno, I put one in when we installed the tub right after the tub overflow/drain kit and tied into the existing drain line.

The plumbing system in that room is as shown in the diagram in the first post.

As for the bad vent, I'm looking into that too. Although it's a bit counter-intuitive as the vanity has no problems draining and it's vent line had no issue whatsoever. Yhat gurgling at the tub now is a symptom. That gurgling sound makes me think that the trap at the tub has been siphoned out. The main problem is that the tub's drain is extremely slow.

Going to work on it this Sunday. Will be snaking that entire drain system again with a more efficient tool. Also going to check the vent stack at the roof/attic to see if there's any clogging going on in there as well.

I appreciate the thoughts/input

So the results are in, and the winner is:

Clogged drain!

I snaked out the entire drain line in that washroom and then tested the tub. We had 1 gallon of water in there and it drained in ~14.35 seconds. The gurgling noise coming from the tub drain/overflow from when we emptied the vanity is gone too.

My best guess is that there was a hair ball in there from before the reno. During the reno, it's possible some sawdust, drywall compound, etc got down there and helped to restrict the flow. Using this better designed auger, I figure I was able to push that clog all the way back to the 3" stack where it will hopefully flow out to the sewer and not cause any problems.

That problem really did my head in. I felt I had snaked that drain out sufficiently the first time and eliminated clogs from the possibilities. Sometimes you just have to go back to step 1 and try everything all over again.

Thanks all for helping me through this. Much appreciated!

We love happy endings, good job! And thanks for following up.