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 Waste Arm max length
Author: HelpMePlumb (FL)

I realize that codes will vary from area to area, but what are typical maximums in waste arm lengths for bathtubs to keep from having a running trap or an S trap? The drain in this spa tub does not line up with the trap in the floor and we need to 90 over to it underneath the tub.



Edited 1 times.

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 Re: Waste Arm max length
Author: SMSPlumbing (PA)

Well S trap are not legal anymore. I assume since you are talking about S traps and such that the pipe comes up vertically. If it is coming up vertically, then you have no choice but to install it that way. Unless there is a trap buried.

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 Re: Waste Arm max length
Author: jimmy-o (CA)

UPC table 10.1 allows 3'6" for a 1½" trap arm.

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 Re: Waste Arm max length
Author: packy (MA)

max is 24 inches from fixture outlet to trap inlet. MA code..

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 Re: Waste Arm max length
Author: hj (AZ)

The maximum length refers to the distance from the trap to its vent, NOT the pipe from the tub to the trap. But, you would have a better drain, and one that would be easier to keep cleared, if you move the trap to where the tub drain is, rather than pipe the tub drain to the trap.

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 Re: Waste Arm max length
Author: North Carolina Plumber (NC)

Since the poster is in NC, he'll need to follow "IPC with NC Amendments". The max distance of a 1 1/2" trap arm is 72". For many years it was 60" but was recently changed.

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 Re: Waste Arm max length
Author: jimmy-o (CA)

hj correctly notes that while we were quoting TRAP ARM length, the pipe the OP is referenceing is the inlet before the trap, not the trap arm itself.

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 Re: Waste Arm max length
Author: packy (MA)

jimmy, that's what i thought too.

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 Re: Waste Arm max length
Author: North Carolina Plumber (NC)

In that case, he needs to move the trap over to the outlet of the tub. Not use 2 90's to offset the inlet to the trap.

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 Re: Waste Arm max length
Author: PlumerDan (CA)

thats what i was thinking too. dig out a little then 45 or whatever it takes to get over and under your outlet of the tub.better draining and better ease of hookup

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