Venting question(s)........

I'm adding on my bathroom and trying to DIY some plumbing... I'm handy, but not real familiar with the laws of plumbing (don't mean codes).

I'm adding a new vanity and bathtub in a new addition. My question is this..... the vanity would drain toward the tub and the tub would be at the exit point to the septic tank... where should the stand vent be located.... before the run, mid-run, end of run?

Thanks
Dave

I would attempt to locate the vent on the vanity drain stack. Use a sanitary tee on the drain stack for the vanity basin, and run the vent out of the top of that tee.

There is no plumbing yet. This is all new so I'm trying to figure out where to vent at..... without doing any research first I started to put the vent stack at the end of the run... meaning the sink would drain toward the tub and they both would drain together out to the septic with the vent at the end of the run (toward the septic). I think this is wrong, correct? The vent stack should be up toward the vanity, yes?

Thanks
Dave

Yes, that is correct.

each fixture would require it's own vent. The vent's can be connected together above the flood rim of mthe highest fixture. The vent's purpose is not only to let sewer gas out of the system but to prevent the fixture's water seal trap from siphoning out and losing the water seal that prevents the gas from coming back out the fixture.

Try your local library. Code books have a lot of good info. This came from a 1985 illustrated UPC book

The horizontal vent connector will drain away from the vertical vent toward the farthest fixture. It doesn't matter which way the sewer drain is going in relation to each fixture as long as the vents are properly sized.

I should have been more specific. It depends upon which codes are in use in your area.

In my area, the codes allow a situation such as what the OP described to be vented with a "wet vent" through the lavatory drain. This is common practice here, and I am not aware of any situations in which a bathroom vented through the lavatory drain to the open air has had venting issues related to it being wet vented properly. Keep the distance of pipe and fittings from the vented line less than 6 feet to the tub, and less than 10 feet to the toilet, and it will meet code.

Thank you all for the info and the images to help me figure this out.

Best
Dave

Mr_David said:

The horizontal vent connector will drain away from the vertical vent toward the farthest fixture. It doesn't matter which way the sewer drain is going in relation to each fixture as long as the vents are properly sized.

Click to expand...

Mr. David, following your drawing I think I may have found an answer to another issue I have.... I'm getting septic smell back in the house, and basically my plumbing in the old part of the bathroom is identical to your drawing minus the stack off the waste pipe. The toilet does not have a stack off of it, but rather vents via the two stacks up stream (refer to your drawing please). My toilet is at the end of the run with no vent stack. I can't really vent it now without (btw... I didn't do this, it was there when I purchased) either busting up concrete, or venting right outside the house as the toilet sits next to an exterior wall and the line is about 3 ft below that wall. Right now the small vanity and tub in this section of the bathroom have a 1.5" vent, vanity is tied to tub just like in your drawing. What do you think?

videopuppy said:

Mr. David, following your drawing I think I may have found an answer to another issue I have.... I'm getting septic smell back in the house, and basically my plumbing in the old part of the bathroom is identical to your drawing
minus the stack off the waste pipe.Not sure what you mean

The toilet does not have a stack off of it, but rather vents via the two stacks up stream (refer to your drawing please). My toilet is at the end of the run with no vent stack. I can't really vent it now without (btw... I didn't do this, it was there when I purchased) either busting up concrete, or venting right outside the house as the toilet sits next to an exterior wall and the line is about 3 ft below that wall. Right now the small vanity and tub in this section of the bathroom have a 1.5" vent, vanity is tied to tub just like in your drawing. What do you think?

Click to expand...

Doesn't matter which fixture vent goes up through the roof. Could be the middle one. Horizontal vents connectors can connect inside the wall , in the ceiling or in the attic. They just have to be above the flood rim of the highest fixture .

The odor could be from a bad wax seal on the toilet. That's the most common sourse.

Mr_David, I have attached a drawing to illustrate what I'm trying to explain. Please advise. Thank you Dave

Wow. So from your scetch I take it that if you pulled the toilet and looked into the flange you would be able to see the waste water from the sink and tub flowing down the drain. Is that what you have now or planning to install?
Reread previous post. Planning
Do you have a depth of main line issue. That's not gonna work .

That is what is there now, and I didn't do it. I'm no plumber, but it doesn't seem right to me. Ugh!

I re-read your last post..... What exactly do you mean by "depth of line issue". Sorry for the questions.

I bad wax seal can leak odor without leaking waste? Thanks Dave

Do some research at a local library
I have an old Uniform Plumbing Code Illustrated Training Manual That has a lot of illustration.
Look for one or something similar and more current . Good luck.
I just did a search on Amazon.com and there old issues for as little $10
A new current 2009 issue will run about $200.