I am preparing to convert two 2nd floor closets into a second full bath (toilet, shower, and lav) in our circa 1940 house. The closets are adjacent to the existing bath so I can gain access to main drain/vent and water supply. Most of the information that I have read recommends individually venting each fixture. The fixtures in the current bath (toilet, separate shower & tub, and lav) appear to make use of the wet vent or combination waste and vent method. This is also the case with the kitchen sink on the first floor, and half bath (toilet and lav) and laundry tub in the basement. We have lived in the house for a number of years without any plumbing problems. I am planning to re-model the existing 2nd floor bath during the project, but not move the toilet or any of the fixtures. Can I use the same wet vent or combination waste and vent method using the existing drain/vent for the new bathroom? If not, should I also re-plumb the existing bath fixtures to include individual fixture venting?

Thanks for any advice,
Craig

Hey Craig,

" Most of the information that I have read recommends individually venting each fixture"
Not on this page or from me you didn't!

Most bathroom groups are roughed in like this.
Toilet connects to sewer main. The toilet wet vents through the lavatory vent. Lavatory connects to toilet drain and runs a vent out the roof or revents back to a vent in the attic off the top the lavs stubout tee. The 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 but also The Standard Plumbing Code Book.
Where ever did you read that each fixture requires its own vent? Regards, Tom

Tom,
Thanks much for your help. A number of plumbing "How To" books (such as Stanley Complete Plumbing) that I referenced seem to show 2'' vent pipe connecting each fixture to the main vent in addition to the drain pipes.
Can I tie the second bath into the existing drain/vent using the rough in you describe.
Thanks,
Craig

Quote:

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Originally Posted by craigbrooks

Tom,
Thanks much for your help. A number of plumbing "How To" books (such as Stanley Complete Plumbing) that I referenced seem to show 2'' vent pipe connecting each fixture to the main vent in addition to the drain pipes.
Can I tie the second bath into the existing drain/vent using the rough in you describe.
Thanks,
Craig

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Yes, You may connect the main drains together and tie the vent back to the old vent with no problems. Keep me informed of your progress. Regards, tom