DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   Plumbing (
-   -   Poor shower drainage/toilet flushing slow (

Weekend Warrior DIY 10-08-2008 08:31 AM

Poor shower drainage/toilet flushing slow
This isn't my favorite topic because I'm so frustrated with this whole thing it's ridiculous.

When we bought our house the second floor bathroom needed gutting, all except the tub was brooken or rotted. We replaced everything, including new PVC piping for the tub and sink.

The sink and tub both run into the main sewer line from the toilet. The whole process looks a little, after the thought, from the beginning but I obviously want a bathroom where I can use everything without plunging the toilet every other day or showering in an inch of water.

Is the problem the venting? Is it the toilet? We got a more affordable one when we renovated it. Do different toilets flush better then others regardless? Any solutions to this problem that you can think of off the top of your heads?

Just a side note, the toilet on the first floor flushes so powerful you'd darn near get sucked in, but the kitchen sink drain is slow.

Add the fact that our house is 135 years old and been through a few renovations over the years.

I'm going to attach an image of what the plumbing looks like now and an image of how I think the plumbing should be to fix the problem, please look at both and let me know if this will solve the problem.

ScottR 10-08-2008 10:37 AM

Hey WW,

Sounds like your vent may be clogged, or poorly done when your bath was upgraded. I don't see your pic yet, but I'm guessing that your slow kitchen drain and slow draining bath are on the same stack running down to the basement?

With the age of your house, you probably have a whole-house trap (somewhere around where the waste pipe exits the basement/crawlspace/etc), unless it's been upgraded. I doubt that's the source of the slow drainage, because in order to see that manifest in the 2nd floor bath, you'd probably first see water backing up into your kitchen sink..

Same with any other clog in the main waste stack below the first floor drains.

Are you comfortable going up on the roof and checking the vent? If you shine a flashlight down there, you should be able to see clear to the basement (or at least the first bend :wink:). If you can see a clog, that may be it.. Birds can nest up there, animals can crawl in there and get stuck, etc..

It may also be that your vent is undersized or improperly done for the new bath. I should wait for your attachment before guessing further, eh?

And no, all toilets are not made equal. If your downstairs toilet is pretty old, chances are it uses something like 3-5 gallons/flush. Newer (past 10-20 years) toilets use 1.6 gal/flush. You'd never get sucked in by one of those.. great for the environment and the plunger salesmen.

Also, even 1.6 gal. toilets can range in "flush power" widely. But a poorly vented stack can cause lack of suction on the toilet making it even worse.


PS - Like I said, I was making the assumption that the kitchen drain is on the same vent stack as the bathroom.. If not, it could just be bad venting on the bath fixtures themselves, and the kitchen is unrelated. Or they could be unrelated anyway.

Weekend Warrior DIY 10-08-2008 10:50 AM


Thanks for the reply, I'm working on the image as we speak to post here.

I only have one vent, which is out the side of the house near the second floor bathroom, but lower on the wall then the floor, that could have something to do with this whole thing, maybe that's why nothing works right. But then why would the first floor toilet still flush so strong, I wouldn't think the water consumption would mean anything there.

Thanks, check back for the image.

Weekend Warrior DIY 10-08-2008 11:48 AM

1 Attachment(s)
Ok, here's an image (albeit crude) to check out and see what you think.

Tell me, do you think it'd work better if the vent stack was vertical and the sewage line coming out of the second floor toilet was closer to the the toilet and vertical?

ScottR 10-08-2008 12:20 PM


Not a bad diagram, actually.. At least you didn't free-hand it in Paint. :)

I should point out here that I'm not a plumber, but... That vent definitely has to exit the house and be open to air at a point higher than the highest drain in the house. In a lot (if not all) areas, it would have to exit through the roof, and be some amount of feet above both the highest drain and the roof surface. Also, depending upon where your fixtures are, it may not be adequate just to move it up..

I'm surprised that you've never seen waste water coming out of the vent from the toilet you have pictured. Are you sure that's the vent for that bathroom, and not for some fixtures on the 1st floor??

If that is where the vent is, you'd need something more like this (attachment coming) for the drains in that bath to flow properly. Do you know what you have in the walls?

ScottR 10-08-2008 12:33 PM

1 Attachment(s)
Ideally this is what you should have (attached)... (I didn't draw it, but shower drain should be vented too, unless it connects right to the roof vent stack I threw in there). Did you do the work yourself, or hire a contractor? I'm not trying to lay blame, just want to know how familiar you are with what's in the walls.

The way you drew it, effectively there is no venting in the bath, so that would explain the problems you're having.. the kitchen drain and downstairs toilet wouldn't have a vent problem though (probably).

Edit: I made an assumption about where your vanity is, but I just wanted to illustrate something across the room..

Weekend Warrior DIY 10-08-2008 01:07 PM

1 Attachment(s)
Scott, being sarcastic about my drawing? :huh:

I couldn't draw it in paint if I wanted to, too complicated, I did it in AutoCad, I'm a CAD operator, these things come naturally.

Attached is what I thought about doing to correct the problem, although now that I see your drawing I might be a bit screwed with my vent idea. I'd have to measure everything out make sure the vent is above the toilet/tank/vanity.

Good point about the sewage coming out the side vent, I'd post pictures but I don't have them with me. It's a scary situation to say the least. Sadly I completely redid a bunch of the pipes in that bathroom and ass-umed that the other piping was fine. Now I'm going to kick myself and cry at the thought of fixing it.

The vanity is directly behind the toilet, then the tub is to the left of that... where you have the sink shown in your drawing.

Here's my proposal (although now I think I might have to add in a vent for the upstairs bathroom on it's own).

ScottR 10-08-2008 02:21 PM

Nonono.. Wasn't being sarcastic! I really thought yours was good.. I was kinda making fun of myself b/c I've used paint countless times to quickly draw something for a post. I used paint for my reply, in fact. :) I'd use Visio if I really had to get detailed, but I suppose you can't beat CAD.

Your last drawing would work, except I think that toilet on the lower level would need a vent directly behind it because of the horizontal(ish) run. I think that there must be a vent within 5 or 6 ft. of every drain, so you might need one behind the tub, too (in my diagram with the tub instead of vanity).

Though the use of AAV's might be allowed in your area -- you should check (Air Admittance Valve). It is basically a valve you put on an indoor vent. It allows air to enter the pipe, but does not allow sewer gas out. They're commonly used in kitchen islands where there's no place to put a standard vent. That would make it easier for your to retrofit, though the AAV would still have to be higher than the drain for which it's venting, and the height and positioning of it is goverened by code.

Weekend Warrior DIY 10-08-2008 02:32 PM

Interesting, thanks. Time to check out plumbing books and contact a plumber for this and another problem.

DUDE! 10-09-2008 06:30 PM

just curious, from reading your other post, having problems with your well,, not always of course, but seems well water and septic systems go hand in hand, so if by chance you have a septic system, your toilet draining concerns may be linked to your system.

Weekend Warrior DIY 10-10-2008 07:31 AM

My septic system is working fine, it's got to be the venting of the system to be honest with you. Someone put in the second floor bathroom, whenever, and tied it into the existing house system and never put any thought into how to do it right.

Nothing is backing up, thank god. I'm going to have a plumber come out and check on the system and then do what he suggests.


Originally Posted by DUDE! (Post 170231)
just curious, from reading your other post, having problems with your well,, not always of course, but seems well water and septic systems go hand in hand, so if by chance you have a septic system, your toilet draining concerns may be linked to your system.

All times are GMT -5. The time now is 01:09 PM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1