# Code Question: distance of trap from stack

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I understand that you don't need to vent a drain if the trap is within 5 feet (or whatever the code specifies) of a vertical vent/stack. What I don't understand is whether this 5 feet is a measurement of only the horizontal distance from the stack of if it is the total length of the drain run. Can anyone clarify this for me? I am trying to put in a washing machine drain on the second floor of my house, and the machine is within five feet of the stack, however I plan to connect the drain at the stack in the basement (i.e. the drain will have a long vertical drop of about 18 feet). Is this okay provided that my drain trap is horizontally 5 feet away from the stack?
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#### DannyT

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it depends on the size of the pipe. 2 inch used to be 5 feet, 1-1/2 is less and 3 inch is more. that is from a vent stack. if more fixtures dump into the stack above this fixture it would need another vent.

#### skowal

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Thanks for the response, but that's not quite what I was after...

What I don't understand is whether this 5 feet is a measurement of only the horizontal distance from the stack or if it is the total length of the drain run from trap to stack.

#### skowal

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My concern is that I have a long vertical drop into the basement where the drain will tie into the stack. I suppose that I could put the trap in the basement?

#### TheEplumber

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My concern is that I have a long vertical drop into the basement where the drain will tie into the stack. I suppose that I could put the trap in the basement?
You can't do either of these options.
The 5' you refer to(varies by code) is the developed horz. length of the pipe from the trap weir to the vent. If it turns vertical without a vent, you have created an s-trap(illegal)
Washer box trap needs to be above the floor of the washer. The stand pipe cannot be more then 30"
(per my local code)

#### skowal

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Thanks for the answer. I drew a pic of what I want to do and it doesn't look like an s-trap, more like a p-trap. Or am I wrong about that? The only reason I ask is that on another forum this method was suggested to me.

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#### Alan

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Thanks for the answer. I drew a pic of what I want to do and it doesn't look like an s-trap, more like a p-trap. Or am I wrong about that? The only reason I ask is that on another forum this method was suggested to me.

Like he stated above, the standpipe (inlet of the trap) cannot be greater than 30".

#### skowal

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Guess I'll have to vent it then. Thanks for all your help guys!

#### md2lgyk

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Washer box trap needs to be above the floor of the washer.
Why would that be?

#### TheEplumber

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Let me clarify. The trap needs to be 6" above the floor. The reason is- UPC states this.

#### Alan

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Let me clarify. The trap needs to be 6" above the floor. The reason is- UPC states this.
I'm just curious if you've run into anyone who will tell you what portion of the trap needs to be 6" above the floor.

I always rough mine in 6" from the bottom of the trap to the floor, no questions asked. :yes: Always wondered, since it isn't specified.

#### Alan

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Also on a similar note :

When they say 6" above the floor, does that mean the rough floor, or does that mean the surface that the washing machine is going to sit on? :wink::yes:

Whenever someone is going to put those pedestals underneath the washing machine we always raise the trap up just to be on the safe side.