Basement drain plan -Vent question

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Birdcool

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New basement bathroom add-on for DYI looking to meet code. My question is if I use a 4" drain line (10ft max run to vent) from Toilet to ejector tank, can I use the 2" ejector tank vent for all 3 fixtures? Or do I have to route a separate 2" vent line where the sink drain drops vertical into the floor drain?

Thank you for insight.

bath drain plan.jpg
 

Reach4

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1. You will have to vent the lavatory with an AAV (if allowed) or a real vent. Can that real vent be tied to the 2-inch vent for the sump? I think so, but I am not sure that is the case for all jurisdictions. The vent lines stay vertical (within 45 degrees of plumb) until they are at least 6 inches higher than the flood level of the lavatory.

2. While venting thru the cover is pretty common for a sealed septic pit, this sure looks nicer for pump access later: https://www.menards.com/main/plumbi...ent-sewage-basin/akp40100/p-1444423405603.htm

3. There is little to no advantage using a 4 inch pipe over a 3 inch. You can use a 4x3 closet bend with the 3 inch pipe, and have a 4 inch riser to the toilet.

4. Pump should be a grinder pump.
5.I am not a pro.
 

Birdcool

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I used the 4" main with the idea that it would qualify as a horizontal wet vent and also so the 8ft run from the WC to the 2" vented ejector tank would fall within the 10ft limit for distance to vent. Is that not allowed?
 

John Gayewski

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Your sink needs a vent no matter what. So the 4"distance is irrelevant since your close to the sink that is your horizontal wet vent. I don't like 4"for almost anything.
 

Reach4

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Your sink needs a vent no matter what. So the 4"distance is irrelevant since your close to the sink that is your horizontal wet vent. I don't like 4"for almost anything.
I think it should be allowed, but I am pretty sure it is not.

What would be allowed is to drain the vented lavatory into the shower trap arm from above. The shower drain would continue to join the toilet. The shower and toilet are then wet-vented. The lavatory drain could go over or around the toilet pipe.
 
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John Gayewski

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I think it should be allowed, but I am pretty sure it is not.

What would be allowed is to drain the vented lavatory into the shower trap arm from above. The shower drain would continue to join the toilet. The shower and toilet are then wet-vented. The lavatory drain could go over or around the toilet pipe.
Huh? The toilet is wet vented by the lav. The vent for the ejector pit is seperate.
 

Reach4

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Huh? The toilet is wet vented by the lav. The vent for the ejector pit is seperate.
Looking at diagram on #1, I think UPC wants toilet the last fixture in a wet vent, or if that has changed, not the fixture before the wet vent enters.

The proposal might be OK with IPC, but OP is in WA state.

If it were IPC, circuit venting, pictured on page 14 of https://www.iccsafe.org/wp-content/uploads/20-18927_GR_2021_Plumbing_Venting_Brochure.pdf would be a case where the 4 inch pipe allows more than the 3 inch would with the dry venting. But that is IPC.

If OP routes around the toilet, thru the slab and/or wall, then everybody is happy.
 

John Gayewski

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Yep upc is that way, but I thought Washington deleted that portion. At least that's what someone else posted previously.
 

wwhitney

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Can it be first?
There is no "first fixture," only a "first junction." And yes, the WC/lav junction can be first (which is the only option if the WC isn't last when there are just 3 fixtures and 2 junctions).

Cheers, Wayne
 

Birdcool

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Thank you in for all the insight. Based on the trend of feedback, my current plan is to add a vent line for sink at the vertical drop into the main line, then connecting that vent into the ejector tank vent. The shower would still need to vent thru main line since both ends are vented. With that, I plan to move to 3" main line. The shower ptrap-to-vent does add up to be 64 inches from nearest vertical vent and code I see for 2" line is 60" max. But I think there is little risk of real world issues with vents at both ends of the main which I use am using as a wet vent at the 28" junction.

The idea to drop the vented lav line down into the shower ptrap was secure venting, but it creates a space available problem working within my concrete floor breakout space and with my drop location limited to within inner wall the line.
 

Reach4

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I understood and agree with the first two sentences of #13.
Is "The shower would still need to vent thru main line since both ends are vented" worded the way you want?
 

wwhitney

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The shower ptrap-to-vent does add up to be 64 inches from nearest vertical vent and code I see for 2" line is 60" max.
The trap arm length is measured from the p-trap to the wye to the wet vent, so it would only be 28" in your drawing above.

Cheers, Wayne
 
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