[dekelemx]

I am in the process of installing a new custom shower in my master bath. I will have multiple shower heads with body sprays.

My questions are:
How gallons per minutes can my 2" drain pipe handle?
I heard that I can put in two drain to increase the rate of flow, is that true?
And if I put in two drains do I need two trap or can I join the two drain into one trap?

Thanks,
dekelemx

[iamgrowler]

I am in the process of installing a new custom shower in my master bath. I will have multiple shower heads with body sprays.

My questions are:
How gallons per minutes can my 2" drain pipe handle?
I heard that I can put in two drain to increase the rate of flow, is that true?
And if I put in two drains do I need two trap or can I join the two drain into one trap?

Thanks,
dekelemx

A 2" trap can handle in excess of 20gpm.

You can join 2 shower drains into a single 2" trap with a continuous waste, but I wouldn't recommend doing so.

I've plumbed numerous showers with multiple thermostatic valves individually supplying body sprays, conventional shower heads, hand held showers and overhead 'rain-head' shower heads -- And have never had a problem with a 2" trap keeping up with the simultaneous operation of all of the valves.

[dekelemx]

Is 20 GPM the rate for 2" pipe and will it be restricted with the drain grate on top?
Is there a 3" drain for tile aplications?
I just don't want to build this great shower and stand in standing water because it doesn't drain quick enough. 3" will provide more drain area than a 2" drain if it is available.

[iamgrowler]

Is 20 GPM the rate for 2" pipe and will it be restricted with the drain grate on top?
Is there a 3" drain for tile aplications?
I just don't want to build this great shower and stand in standing water because it doesn't drain quick enough. 3" will provide more drain area than a 2" drain if it is available.

20GPM is the rating for the trap, trap arm and drain -- And I don't see the drain grate being a problem.

There are 3" drains available in both plastic and cast iron, but you will need to provide a 3" trap, trap arm, drain and a 2" vent for the drain to operate as intended, as well as to pass inspection -- And if the master bath is above a living space, you will need to factor in that a 3" p-trap with the 2" vent rolled horizontally above the centerline of the 3" inch drain and sloped upwards 1/4" per foot is not going to fit inside of a conventional joist bay.

Really, a properly roughed-in 2" drain keeping up with 3 or 4 thermostatic shower valves running simultaneously is not going to be a problem.