I am remodeling my bathroom and I have a question. Behind the toilet, sink and bath tub is a brick wall. I want to leave the wall exposed, but the problem is all my drain venting is against the wall. There is a crawl space under the bathroom with very easy access. Is there some way for me to hide all the venting pipe without having it behind the fixtures along the wall? Can I somehow run it underneath and up one of the other walls?

Toilet is the only drain that should not have horizontal vent. But there are exceptions...

First, I have 3 questions to ask:

1. How deep is your crawl space ?
2. How low is your main horizontal sewer in the crawl space in relation to the bathroom floor?
3. How far away is the wall that you could use for venting your toilet ?

The crawl space is 42" tall. The horizontal pipe run right along the bottom of the floor and out of the crawl space. Which then runs into the basement to the sewer pipe. I have two walls I can use, each about 5' away.

You have lots of space to play with. So: run 3" vertical drop from toilet ring towards the bottom of your crawl space. Before you turn from vertical to horizontal, install 3"x2" Y fitting with th 2" outlet aiming towards your wall. Run 2" pipe to that wall under 45 degree slope. Once under the wall, use second 2" 45 to go up . Continue to your attic as you please. Also, continue with 3" pipe towards you existing sewer and connect.

That definitely sounds easy enough. The other question is... what about the shower and sink? Can I incorporate those into the same pipe?

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Originally Posted by caseytow

That definitely sounds easy enough. The other question is... what about the shower and sink? Can I incorporate those into the same pipe?

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That would depend on what code you're in. My code gives you a easy lay out in drainage and venting. Our 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, Tom

Thank you for your advice, it will help out greatly.