Critical distances for toilet, bath & kitchen sinks and shower from vent

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Chuck B

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Re: Small up north cottage

Wondering how far I can run the drain lines from the above fixtures before I reach a vertical vent that will eventually terminate at the roof. Understand this is called the critical distance. Also, can say a bath sink and shower DRAIN line be placed between the toilet drain (going downstream) and the "y" or "t" to the roof vent, which then travels to the septic tank and if so how close to the toilet flange?

Am I correct in that at least one roof vent is required, and that is needs to be a minimum of 3" diameter, and protrude at least 1' above and below the roof?

The shower currently drains into a dry well as the septic system at present is only a holding tank that needs to be pumped out and not a drain field. Since I am completely plumbing the dwv system from under a tight 24" crawl space and want to do this just once, is there a way I could make some sort of "y" or "t" connection for the shower drain so that it could drain to the dry well NOW until I have a new field installed? Then switch over to the septic system later on since the largest volume of water necessitating costly pump outs come from the shower . Would a valve work on a two-inch line and could that cause any problems??

How large does the vent need to be if the four fixtures mentioned above are connected, ie. shower, bath and kitchen sink, and toilet? Is it also correct to attach the kitchen sink vent a minimum of 6" above the highest drain fixture, in this cast the kitchen sink? Thanks for your help. Also are the Studervents noisy (sucking sounds?) if I choose to use one inthe bath sink and kitchen sink instead of connecting to the roof vents.

Also, what is the proper pitch upwards toward the vent roof lines to provide for drainage to the septic drain? And is this accomplished by simply tilting or midly straining the pipe to pitch with supports in the attic (and how close do these need to be installed)?

Thanks alot guys!

Michigan IPC effective Statewide

https://terrylove.com/forums/forumdisplay.php?28-IPC-Plumbing-Code-Questions
 
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Tom Sawyer

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all those answers depend on what code you are under. I suggest you contact the local building/plumbing inspector and get his take on things.
 

hj

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1. distances from the trap to the vent vary depending on the code.
2. Again according to code. You might need one 4" vent, or one 3" vent, or get by with two 2" and a 1 1/2" one, or some other combination depending on the fixture locations and code requirements.
3.ABSOLUTELY not. Otherwise leaving the valve open would allow ANYTHING to flow to the catch basin bypassing the septic tank. And a valve would create an obstruction once the flow was diverted.
4. The vent size depends on the fixtures it is serving, but often is determined by the size of the sewer line entering the
building.
5. The vents must drain back to the sanitary system. How this is accomplished, and where supports have to be is determined by their placement and sizes.
 
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