I am remodeling a second floor bathroom and was surprised to find that there is no vent on any of the drains. I have a 3" line that t's off to a shower and tub drain and then dead ends at the closet flange. Is this to code? My real questions is: Will a 2" vent suffice if installed 12" ahead of the closet flange?

I am remodeling a second floor bathroom and was surprised to find that there is no vent on any of the drains. I have a 3" line that t's off to a shower and tub drain and then dead ends at the closet flange. Is this to code? My real questions is: Will a 2" vent suffice if installed 12" ahead of the closet flange?

You say nothing about a lavatory. Where does the bathroom sink drain to and is it vented? Every fixture that has a trap must be vented. You are discharging a major fixture, (the toilet) past a unvented minor one, (the tub/shower) a vent installed 12" ahead of the closet flange won 't vent the shower. Let me show you how a typical bathroom will go in. Most bathroom groups are roughed in like this.
Toilet connects to sewer main or the stack vent. Lavatory connects to toilet drain and runs a vent off the top the stubout tee out the roof or revents back into a dry vent in the attic.. The toilet wet vents through the lavatory vent and the tub/shower connects to the lavatory drain and is wet vented by it. This is a normal rough in and is acceptable both by local and state codes and also The Standard Plumbing Code Book in 90 percent of the country. Check your local codes to make sure you're not in the excluded 10 percent.. The vent off the lavatory may be run out the roof or revented back into a dry vent in the attic or if you're reventing back into a fixtures dry vent you must make your connection at least 6 inches over that fixtures flood rim. Good luck and thank you for rating my answer. Tom

Speedball1,
Thanks again for your reply. Upon further investigation I found that there is a vent but it looks really strange. Please see the attachment for details. This is a rather new home, about 7 years old, so I am sure this was done by the original builders plumbing contractor. It seems to work OK. Given this layout, since the hood is open, would you recommend adding a vent after the closet flange?
Thanks again for your help.

A 7 year old home with no alterations was likely built to code, check with the building department in your two to see if a inspection was done. If it isn't broken, don't fix it. If you are moving fixture please explain further, thanks.

Ballengerb1,
The planned plumbing modifications are basically,
1. Move the closet flange about 2 feet further out from its current location.
2. Shorten both the shower and tub drops about 1 foot.
Everything else can remain the same.
Thanks for your help.

Hi shark...

Looks like your toilet and shower are WET VENTED through the SINK DRAIN/VENT... Here, as Speedball pointed out, the sink vent actually acts as a vent for the sink , the shower and the toilet. The only thing contrary to plumbing code is that the sink vent should run 2" full-size until it connects into another 2" vent in attic..? So someone missed that at inspection... I guess. This is perfectly acceptable plumbing (except for 1.5" reduction in vent) in most of the U.S.A.. You should not have to add a 2" vent for the toilet, but may want to increase the lavatory vent to 2" if possible... ;)

Anyway, moving the fixtues as you presented should be fine.

Any more questions just pop back and let us know... ok?

MARK

MassPlumber2008, Thanks for the reply. I really appreciate your help. The lavatory vent runs up the wall behind a huge mirror that is glued to the wall. I doubt that it can be removed without breaking it, so changing the 1.5" vent would be difficult.

Old school will tell you that an 1.5" vent is better than NO vent... ;) If your toilet is sluggish or bubbles/gurgles when you flush then you may want to install a new 2" vent... but I'm betting it is not necessary.

MARK

I'm old school and I'm a great fan of, "If it ain't broke don't fix it" Follow Marks advice. Good luck, Tom

Thanks guys. I will leave it as is. Thanks again for your help.