Drain size for tub/shower combination

[Home Girl]

I am reading that the tub drain should be 1 1/2" while a shower drain should be 2". If a tub/shower combo is installed, can a standard tub drain be used, or does that require a larger shower drain?

[FloridaOrange]

What do you mean by tub/shower combo? Tub with a shower head? If so the 1-1/2" drain will work. The idea is that the tub can provide holding space for water if the drain is slow, a shower doesn't offer much if any holding before you overflow the curb.

[geniescience]

The smaller size drain works.

It also works for showers too, and that used to be the size required by "Code" too. I think that bigger houses and longer distances are the reasons why its size was increased to 2".

.... idea ... holding space for water if the drain is slow, a shower doesn't offer much if any holding...

[Inspektor Ludwig]

Yes, you can have an 1 1/2 drain for tub/shower combo.

[hj]

You are too young to remember when a shower was permitted to have a 1 1/2" drain. I am also.

[FloridaOrange]

You are too young to remember when a shower was permitted to have a 1 1/2" drain. I am also.

Florida used to require all under slab plumbing to be minimum 2". Now they don't, along with allowing CVPC (with joints) underslab....

[plumbergreg]

The smaller size drain works.

It also works for showers too, and that used to be the size required by "Code" too. I think that bigger houses and longer distances are the reasons why its size was increased to 2".

The sizes in the code are the minimum size not the required size