Hello all!

I stumbled upon this forum... what a godsend!

Anyway, here's a question for the plumbing experts. I have two bathrooms, each with one toilet and one sink. All four of these items are vented through a single 2" pipe up to the roof. I've been having a bit of trouble with the toilets backing up, and I'm wondering if my single 2" venting is insufficient for two toilets and two sinks. I'm not even sure that this would affect the performance of the toilets, but thought I'd ask the question.

My job WAS inspected and passed inspection, but I'm wondering if this is something that the inspector might have missed.

Any thoughts? Any help you offer in greatly appreciated. Thanks in advance!

John in California

Hey John from California.

Unless that 2" vent is blocked it should be enough to service the fixtures you discribe. Are the toilets new? Do you hear a "gurgle" from anywhere when you flush or drain? Do both toilets back up or just one? Are the bathrooms back to back? Do the toilets back up and overflow or do they fill to the top and swirl around and drain slowly away? City sewer or septic tank? I'll wait on your reply. Tom from Florida
,

Tom,

Thanks for your response. Here are my answers:

1) The 2" vent is brand new and should not be blocked, unless water can into such a vent or something (not sure how the venting works).

2) Toilets are brand new Toto Drake toilets. I'm going to try the Kohler air-assisted toilets unless someone talks me out of it.

3) The bathrooms are back to back. One bathroom is at a higher elevation (by about 12"). When the system gets stopped up, it seems more likely that the lower of the toilets backs up more than the upper. And when that happens, flushing the upper toilet makes gurgling sounds come out of the stopped up (bottom) toilet.

4) The toilets can back up and overflow (or leak out from under the toilets). Usually, we have to call a rooter company. They have sent a camera down the line and the stoppage seems to happen about 30' from the toilets typically, although on camera we can't really see any obvious reason why.

5) We are connected to the city sewer line.

6) The city sewer line is about 70' from the toilets and we have taken the camera the entire length... no major obstructions or anything. And when we flush, water flow looks good even 60' out.

I have noticed that it seems like if both toilets are flushed at the same time, there is a greater likelihood of a problem. I forgot to mention that this is a commercial business, so having two people flushing close to one another isn't out of the question. Anyway, that's why I was wondering about the venting and whether that would have anything to do with the issue.

Any thoughts on the Kohler air-assisted toilets over the Toto Drake? I gather that the Kohler will perform better at the point of the toilet, but I don't know if that will translate into stopping blockages that occur 25-30' feet out.

I do have one employee who eats a large bowl (at least one) of oatmeal every day, and the camera operator thinks that that might be the problem... the water doesn't really push the oatmeal down the line, it just passes through the oatmeal... that's what we're thinking.

Anyway, any help would be appreciated.

Thanks again,

John

So when you say

4) The toilets can back up and overflow (or leak out from under the toilets). Usually, we have to call a rooter company. They have sent a camera down the line and the stoppage seems to happen about 30' from the toilets typically, although on camera we can't really see any obvious reason why.

Do you mean there is a blockage forming sometimes?? If yes:

Someone may be flushing some inapropriate stuff in the toilets blocking up the works... ie... tampons. Just a shot in the dark but this can happen especially in a public place.

Tom

Hey Tom,

Well, I have a very small company (5 employees) and no one is putting tampons down there. One guy has been eating oatmeal (did I say that already) and it might not be flushing down and through completely, thus restricting the pipes. Any other suggestion?

Would you happen to know if the Kohler air-assisted toilets would help with things 25- down the line or do they only help right at the toilet itself?

Thanks again.

John!

Before you switch out the toilets I would determine that you have adequate grade. Has the camera been run from the toilet area? If not, where has it been run from. If your drain has 1/4" fall per foot of run sloped towards the street, you should be good. The camera should see that if you run water while you are watching. If you decide to change the toilets, I would do one at a time and see if that makes a difference. Usually the camera is a tell all. I just wonder if it is being put down at the right place. Also you may want to double check the vent. As far as water coming from under the toilet, when things are going smooth again you will want to replace the wax rings that are under the toilets. Sometimes the flange sits a little low and the plumber needs to add part of another ring to it. In extreme cases the flange needs to be replaced, but of course this is all secondary to your main problem. Ive never heard of oat meal being a problem. Usually if there is stool problem it doesn't make it past the toilet. Good luck.

Hey, thanks for the answers so far. OK.. here's more questions/comments.

We have put the camera down a few times. Things don't look bad on the camera... we can't detect any breaks in the pipe, nor can we detect any obvious problems. HOWEVER, before I opened for business, we did some earthquake retrofitting, which included the installation of a couple of large posts supported by large concrete footings. The existing pipe runs through the footing... one of the things I'm wondering about is whether, in the construction of said footings, the pipe might have gotten "adjusted" such that there is at least a slight bow somewhere, forcing the water to run uphill at some point. If that's the case, then I presume the best idea would be to rip up the pipe and lay new pipe, making sure that sloping is proper.

On the other hand, the plumber that put the camera down does not think that there is any problem with the sloping. He thinks it's a problem with the pipe being old and the calcium build up "catching" waste as it does down, thus creating the blockage. He believes that we should shoot a fiberglass liner into the pipe, thus creating what he says would be a very slick surface to which nothing will stick.

I'm at a total loss, and it appears that both approaches would cost about the same (low thousands of dollars).

Anyone have any thoughts about this?

Thanks again so much, everyone.

I really appreciate everyone's comments!

John

Good Morning John,

I question your plumbers analysis of the problem. The discharge in a sewer pipe builds up grease and gunk on the pipe walls. This makes the sewer pipe walls slick. I would be more inclined to believe mineral build-up,( calcium) in a water pipe then in the drainage system.
You say, "One of the things I'm wondering about is whether, in the construction of said footings, the pipe might have gotten "adjusted" such that there is at least a slight bow somewhere, forcing the water to run uphill at some point. If that's the case, then I presume the best idea would be to rip up the pipe and lay new pipe, making sure that sloping is proper."

If that is the case then the discharge would flow down to "the bow" in the pipe and start to run up hill. The flow would then began to lose velocity and start to drop solids. As the solids build up then blockage would begin to occur. If the cost of replacing the sewer pipe is the same as shooting a membrane down the pipe then it's a "nobrainer". Replace with PVC.
Good luck, Tom

Hi Tom and thanks for your thoughts...

I might be wrong, but I had thought that my plumber had said calcium. The pipes are very old and the pipes also saw no use for a several year period (I'm in a commercial building that was vacant for several years prior to my taking it over). Anyway, there's a bit of "buildup" on the pipes that (we think) might be constricting things, catching paper, etc such to the point of blockage. That's the thinking there.

Yes, laying new pipe is a "no brainer", although here in a commercial building in L.A. it would have to be cast iron due to codes. But more importantly, we'd have to rip up my beautifully finished polished concrete floor, which would most likely never look the same as it does right now. Think "art gallery polished concrete floor" and you'll have a better idea of why I'm looking for solutions which might be non-invasive in that way. Don't get me wrong, if I KNEW there was an upslope somewhere, I'd tear the floor up without hesitation. But I don't want to do that unless I feel that it's absolutely the right thing to do...

Thanks again if you have any thoughts...

John!

Hey John,

If it were me, and before I went to any expense to replace pipe, tear up my floor or shoot a membrane down the pipe I would do my best to localize the problem. Inside or outside problem? I would dig down to where the sewer exits the building and if there wasn't a cleanout I would install one. The next time it stopped up, open up the clean out. If you have standing water in it or water gushes out then the problem's downstream from the clean out and outside the building. If the clean out's dry and you're still stopped up the blockage is in the house sewer. Let me know what you think. Tom