Direct vent toilet into soil stack?

[LogHomeDIY]

Hi all, and thanks for the awesome resource. I'm building a place in the CO mountains with a heavy dose of DIY and I'm currently working on the DWV system. I've pretty much got it all planned out - with lots of help from browsing this forum - but came across this article and I wanted some clarification:

https://homeguides.sfgate.com/vent-bathroom-toilet-37126.html

The article basically says that if your toilet is within 6 feet of the soil stack for 3" pipe or 10' for 4" pipe you don't need a separate vent and can tie directly into the soil stack. I can't find any reference justifying this, other than the concept of a waste stack vent which IPC specifically states can't have any WC or urinals discharging into it.

I have one toilet that is close enough to the soil stack that getting a vent in will be tricky, though I think I have it worked out. It would make my life a lot easier if I could just tie right in like the article says but I don't think that's going to be kosher.

Any insight as to whether the article is accurate? My best guess is that it likely falls into the "would probably work but isn't code compliant" category.

 

[Terry]

Normally a toilet would be vented before entering a waste stack. For instance, an upstairs bathroom draining down the stack would cause problems for the toilet on the lower floor if it wasn't vented first. I don't think the person writing that article had ever done any plumbing.

 

[Sponsor]

 

[LogHomeDIY]

Thanks Terry. Guess you can't believe everything you read on the internet. Who knew?

 

[Reach4]

Normally a toilet would be vented before entering a waste stack. For instance, an upstairs bathroom draining down the stack would cause problems for the toilet on the lower floor if it wasn't vented first.

If that second story toilet did not have that vent line shown, wouldn't that toilet be properly wet vented if the pipe below the lavatory santee were 2 inch?

 

[hj]

NO! The toilet would have to be connected TO the lavatory drain, in which case it would have to be 3" to the toilet connection and 2" above it.

 

[Reach4]

NO! The toilet would have to be connected TO the lavatory drain, in which case it would have to be 3" to the toilet connection and 2" above it.