One P trap or two?

[mpire]

I am splitting a bathroom in half and adding an additional tub.

The tubs are only a 2x4 apart back to back.

Using the existing drain, splitting it in two using a long radius y adapter.

So the drains are exactly 32.5 inches apart.

Do I need one P trap before it goes into the larger 2" drain pipe 18 inches away, or do I need one for each tub?

Also, a 1.5" glue in P-trap is pretty standard stuff.

 

[firebirdparts]

Philosophically, it wouldn't really be necessary. I don't mean that to be a commentary on whatever the code is. With one p trap, what you'll be able to do is talk to whoever is in the other bathtub through the drain. I don't think that is going to burn the house down or anything.

 

[mike93lx]

I would use separate traps. Also 2" for a tub or shower.

Use a trap with a clean out, as well

 

[rlitman]

I would use separate traps. Also 2" for a tub or shower.

Use a trap with a clean out, as well

2" is code for showers. 1.5" is code for tubs, but there's no harm in stepping up, and since it's going into a 2" drain anyway, that makes more sense to me. Certainly you need 2" if you're using a single trap, and I wouldn't consider having a shower above it.

Ideally, I prefer a trap that can be disassembled. If that's not possible, then I'd always have a cleanout at a minimum.

As for one vs two traps, I guess it could be done with one, but only if you take into consideration how rushing water from one side could enter the other. If you have a Wye placed correctly, that may not be an issue, but if they meet at a Tee, troubles could ensue.

 

[mpire]

I would use separate traps. Also 2" for a tub or shower.

Use a trap with a clean out, as well

I got two traps, might as well use them.

They are tubs, the drains are only 1.5 inches on the tub and the tub kit. It steps up to 2 inch pipe at the Y connection.

All the connections are the wide radius street elbow style other than the P trap which is kinda tight coming out.

There will be NO access to this after I close up the floor. Downstairs is someone else's place so I am probably being a little OCD just to make sure I don't have future headaches.

Once I get everything glued up, I will have a professional plumber friend come look it over for the customary 1 hour service charge and not have to do the plumbing inspection twice.

 

[TRWham]

I'm not saying it won't work, but it may be a code violation. IRC plumbing code calls for one trap per fixture with a few exceptions, but bathtubs are not one of those. The traps should be the same size as the drain in the fixture and not larger than the pipe into which they discharge. I would trap them individually at 1.5" then wye them together into the 2" line.

You posted while I was typing. Sounds like you have it figured out.

 

[johnnyradiant]

I love traps that can be taken apart, ones that have a trap drain, and even those that have the swivel connection in the trap for those awkward vanity refits on occasion, but for a tub, especially one not above an open ceiling - glued traps are my favourite flavour.

 

[signcrafter]

How are you venting these two tubs now?

 

[ishiboo]

Two traps.

If it's going to clog, it's probably going to clog at the trap.

 

[Norcal]

But 2 tubs cannot share a 1 1/2" line.

 

[pcmeiners]

I would use separate traps. Also 2" for a tub or shower.

Use a trap with a clean out, as well

Agree, I would go 2" all around. NYC dropped to 1 1/2" many years ago, royal pain for everything, constant clogs. Not sure what the code is now in the city.

 

[LS6 Tommy]

You need individual traps and individual vents.

Tommy

 

[flat350]

Run the 1 1/2" traps tied together at the 2",2 traps on the same level should be good with a common vent.A C.O at the trap is worthless with no access to it,if they backup rod it through the overflow plate,that's what it's for.