How much able to go on one 2” drain?

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Kevinjm4

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I am routing my laundry room waste currently, and it is convenient for me to have the laundry mud sink connect to my double vanity/tub 2” drain line in the bathroom, before connecting to the 3” toilet. (Mud sink to lav drain (estimate) 12’. if this is critical I can get better than an estimate) The mud sink is vented already at laundry room, and the tub and toilet are wet vented through the double lav in the bathroom.

So, first the double vanity drain at 2”, then the laundry mud sink wyes/combos into the double vanity drain. Then the tub wyes into the same lav/mud 2” drain pipe.

Three fixtures on one 2” line, is this ok?
Then those three will wye in with the toilet into a 3”.

The tub and WC are wet vented through bathroom lav drain. Does adding the mud sink affect this at all? Mud sink will already have been vented at its own fixture.

For what it’s worth 2” Washer has its own drain that goes straight into the main a ways down the line. Mud sink too inconvenient framing wise to be connected to washer.
 

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wwhitney

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Three fixtures on one 2” line, is this ok?
Yes, but see below.

The way you answer this question is to first look at UPC Table 702.1 to find the DFUs for each fixture: 1 for each lav, 2 for the laundry sink, 2 for the bathtub, for a total of 6.


Then you look at UPC Table 703.2 and see that a 2" horizontal drain can carry 8 DFUs (excluding WCs). So no problem.


The tub and WC are wet vented through bathroom lav drain. Does adding the mud sink affect this at all? Mud sink will already have been vented at its own fixture.
Yes, horizontal wet venting is limited to bathroom group fixtures, so once the laundry sink comes in, none of the downstream fixtures can be wet vented by the lav. So unless you want to individually vent the tub and the WC, you need to bring the laundry sink in downstream of the lav, tub, and WC.

Cheers, Wayne
 

Kevinjm4

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Yes, but see below.

The way you answer this question is to first look at UPC Table 702.1 to find the DFUs for each fixture: 1 for each lav, 2 for the laundry sink, 2 for the bathtub, for a total of 6.


Then you look at UPC Table 703.2 and see that a 2" horizontal drain can carry 8 DFUs (excluding WCs). So no problem.



Yes, horizontal wet venting is limited to bathroom group fixtures, so once the laundry sink comes in, none of the downstream fixtures can be wet vented by the lav. So unless you want to individually vent the tub and the WC, you need to bring the laundry sink in downstream of the lav, tub, and WC.

Cheers, Wayne
And by downstream this is any distance from the last bathroom fixture being went vented, which for me is the toilet. So having the laundry tie into the 3” just after the toilet ties in with the tub/lav, is fine?
 

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wwhitney

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Yes, just after is fine. It could be consecutive fittings: the wye for the WC, followed by a wye for the laundry.

Cheers, Wayne
 
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