Proper Venting Help

[woz442]

I have a toilet, tub and lav that was installed by a previous owner in my basement. Nearby is the utility room containing the washer and a slop sink, also a floor drain.

I recently got water up through the tub drain during a heavy rain, flooding the bathroom. There was eveidence that this had happened previously once I really starting investigating. I am remodeling the basement and want to fix the problem, so I removed the tub and will not be replacing it. I am relocating the lav and will be connecting it into the vent stack, however the toilet does not have a dry vent. When the washer drains into the slop sink the toilet is bubbling and when the basement was flooded and water was going down the floor drain it was backing up back into the basement via the tub drain.

I will be capping the tub drain in the floor but am wondering if there is anything I can do about the toilet burping when the slop sink in draining. The toilet is approx. 7-8' from the stack, am I reaching the limit if what a wet vent can handle or is there something else going on?

[Redwood]

I would suggest getting your main sewer lin checked out to see if it is a problem with your line causing the backup or if the city line is the culprit.

Solution varies with diagnostic results.

[woz442]

Thanks! So your first inclination is that it is not a venting issue from what I've described?

[Gelo30]

So your first inclination is that it is not a venting issue from what I've described?
I think it is, but if not what do you think it might be?

[woz442]

I think it is too but as I am not a master plumber, although a degreed mechanical engineer, I was surprised to receive the reply I did from the first guy that I should be checking to make sure my drain is clear. If the slop sink draining causes the toilet to burp in bowl, that sounds to me like improper venting somewhere.

[jadnashua]

If there's a partial clog, you could get those symptoms. If the sink isn't vented, depending on the size and length of the pipes, you could get that problem.

Unless your city sewer is undersized (often if it isn't separated from the surface water, during a big rainstorm or heavy snowmelt, it might overwhelm the sewer), you could get that symptom. If you have a septic tank, you may have problems, field failure, saturation from spring melts, or the tank is full and needs to be pumped. If the pipes have negative or flat pitch, you could have those problems. A belly somewhere is all it could take to create a clog and back things up. A cracked pipe that catches some debris can create a temperary partical clog.

No one answer is always right...

[woz442]

Thanks! Actually, this all occured with the sink totally removed. Initially the tub was vented vertically, then ran behind the sink where the sink vent joined up, then the vent ran vertically again for about 1-2', then turned and ran horizontally for about 5', then turned DOWNWARD and ran a foot or so, then turned horizontally and ran to the stack. I thought that having the vent go up and over the bathroom then down again was really wrong so I cut it out and am going to rerun it. That's when I noticed this other issue and I want to do it once and do it right.

[jadnashua]

A vent needs to be run with slope just like a drain, otherwise you can plug it up with condensation, rain, or other sources of moisture and crud. there are rules about the horizontal verses vertical run lengths, and where they can occur, but I don't remember.

[Redwood]

The water backing up in the tub drain is pretty much a giveaway.
The line is clogged.
When a line floods the vents cease to work because they are under water.

I'll standby my original statement.

You may have some venting issues but they will not cause drains not to drain or, have water come up in them.

[hj]

Vents do not make things drain better, in fact in many cases they would drain better without a vent, which can be a problem. Nor do lack of vents, by themselves, cause poor drainage. If there is any problem with the venting, it is because you have an more serious problem and the improper vent is just making it more evident.

[Rich B]

I am not a plumber but I can agree. I wrestled with a slow and backing up kitchen drain on a double sink. I convinced myself it was because there is no vent on this sink. I added a Studor vent and replumbed both sinks. These drains soon completely stopped draining. I went on another plumbing website looking for advice and a very experienced plumber told me the exact same thing...a drain will not back up or stop draining becasue of a lack of a vent......It might be slow but thats all. I removed a cleanout plug in the old galvanized pipe and found it blocked solid with rust and grit. It took me three tries with a Home Depot hand operated small snake to clear the pipe......I have replaced all that galvanized with PVC....I did not believe it was a blockage at first but found that to be the problem and it was slow draining and backing up for a long time.......

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