Basement Bath Wet Venting

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Someday997

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I am getting ready to finish my basement and I am planning on putting in a full bath. When the house was built the builder did install a sewage ejector, but did not install any under the slab pluming for the fixtures. The sewage ejector is plumed to the main discharge line and vented with a dedicated 2” vent line. The plumber did drop and cap a separate 2” vent for future finishing.



While I feel like I have a handle on the drain lines the venting and amount of venting necessary is confusing me a bit. My initial plan was to utilize the sink vent (2”) to wet vent the shower and toilet, but I am not sure if that would be sufficient venting for a full bathroom group. The vent would run behind the walls to the capped vent line which is about 25’-30’ away. I can plenty of slope on it running it behind the walls. With the main 3” line going directly into the grinder pit does the 2” grinder vent also count for the bathroom group.



I have attached two pictures of the potential layouts, I am leaning toward the first one as it makes it easier to run a second 2” vent. Running the lower “potential vent” would make it easier to keep the vent line vertical off the main line over to the wall to avoid running horizontal which I believe is a no go for inspection.



Any help, issues, or suggestions would be greatly appreciated. Thanks.

Bathroom Primary Pic.png
Basement Secondary Pic.png
 

wwhitney

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Kansas uses the IPC?

Since you sewage ejector is already vented, your bathroom venting is a completely standard situation. The IPC allows an entire bathroom group to be vented with a single 1-1/2" atmospheric vent (but 2" is fine), or an AAV. The vent is taken off the lav trap arm, before the trap arm falls one pipe diameter. Then the lav drain is your wet vent. That means the the shower trap arm has to join the lav drain before that trap arm falls one pipe diameter. The WC doesn't have a a fall restriction.

In other words, if your lav is properly vented, then either diagram works, with no need for the extra vents shown as dashed lines. What matters is the total fall from the shower trap to the shower/lav wye, which can be no more than 2" while the fall is at least 1/4" per foot. But that allows 6' easily.

If I'm mistaken and you are under the UPC, then the lav vent and drain need to be 2" for wet venting, the shower trap arm is limited to 5', and the distance from the WC closet flange along the pipe to the 3x2 wye is limited to 6'.

Cheers, Wayne
 

Someday997

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Kansas uses the IPC?

Since you sewage ejector is already vented, your bathroom venting is a completely standard situation. The IPC allows an entire bathroom group to be vented with a single 1-1/2" atmospheric vent (but 2" is fine), or an AAV. The vent is taken off the lav trap arm, before the trap arm falls one pipe diameter. Then the lav drain is your wet vent. That means the the shower trap arm has to join the lav drain before that trap arm falls one pipe diameter. The WC doesn't have a a fall restriction.

In other words, if your lav is properly vented, then either diagram works, with no need for the extra vents shown as dashed lines. What matters is the total fall from the shower trap to the shower/lav wye, which can be no more than 2" while the fall is at least 1/4" per foot. But that allows 6' easily.

If I'm mistaken and you are under the UPC, then the lav vent and drain need to be 2" for wet venting, the shower trap arm is limited to 5', and the distance from the WC closet flange along the pipe to the 3x2 wye is limited to 6'.

Cheers, Wayne
Thanks for the info, I did confirm my jurisdiction is following the IPC. This will make things much easier not having to separate the vents and I can easily hit the fall requirements before hitting the shower/lav wye.
 
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