Using 1 1/2" drain pipe in condo

[andywc]

I want to replace the bath with a walk-in shower in my Condo. This will re-use the drain as a floor drain for the shower.

The existing piping in 1 1/2" and I cannot change that as that would require touching the central drain and my downstairs neighbors ceiling, and the board will not allow that.

In Arlington County, Virginia the IPC 2000 has to be followed. This states that the shower waste outlet has to be 2" (417.3). However, code 709.1 says that I can use a 1 1/2" trap with a shower.

Would it be code compliant to use a 2" shower drain connected to a 1 1/2" trap and drain pipe?

Anyone know or had this problem?

[jeffreyhel]

I can't speek for IPC since here in NJ we use a different code but here in NJ it MUST be 2".

[Gary Swart]

I'm just a DIYer, but it is my understanding that you should never reduce the size of a drain. In other words, stay 1-1/2" all the way to the main drain. Ideally, a shower should have a 2" drain, but in reality, many showers work just fine with 1-1/2". This fact of course will not impress a code inspector, so you should check with your local authorities to see what they will/will not allow.

[geniescience]

How far to the stack, Andy? This will determine how much the 1 1/2" would be slower to drain than a 2" pipe. It will work.