I am putting in a bathroom in my basement. It is new construction and has the bath already roughed in for a sink, toilet and shower. The shower drain is about 14" away from where it actually needs to be (not sure what the builder was thinking). I have already demoed the concrete from the existing drain location to where I need it relocated (14" away). The existing drain does have a trap that is 20" below the concrete surface level tied into the 4" toilet waste drain running at about a 45 degree angle. My question is;

1.) Can I tie the new shower location directly into the old shower drain and use the existing trap since I have about 20" of vertical pipe to work with?

2.) If no... and is because I need to have a new trap installed in the new location directly below the drain, can I still have the other trap remain and then just tie into the 20" of vertical pipe?

I am trying to minimize my amount of concrete work for only having to move the drain 14". Thanks

http://www.amsa.org/images/Drain1.jpg

1.) Can I tie the new shower location directly into the old shower drain and use the existing trap since I have about 20" of vertical pipe to work with?

No, The trap should be directly under the shower drain.

2.) If no... and is because I need to have a new trap installed in the new location directly below the drain, can I still have the other trap remain and then just tie into the 20" of vertical pipe?

No Again, You can not double trap a fixture.

Also you may not discharge a major fixture, (your toilet) past a unvented minor one,( the shower) The shower MUST be vented. If this is the way the plumber left you then he did a poor job. He should have connected the shower to the lavatory and be wet vented by it, read on. Most bathroom groups are roughed in like this.
Toilet connects to sewer main. The toilet wet vents through the lavatory vent. Lavatory connects to toilet drain and runs a vent out the roof or revents back into a dry vent in the attic off the top the stubout tee. The shower connects to the lavatory drain and is wet vented by it. This is a normal rough in and is acceptable both by local and state codes but also The Standard Plumbing Code Book.
You ARE running a lavatory vent aren't you? Regards, Tom

In the diagram the toilet on the left is attached directly to the main waist pipe which runs completely across the basement from the left side of the house to the right. The shower drain appears to be attached to the toilet waist line and has a trap under it. The sink drain is also the vent pipe that runs straight up and out the roof. Both the shower and sink are 2" pipe. The sink comes down and the has a T stub off of it that is 1.5" with a cap. The sink vent pipe attaches to the main waist line... the same one the toilet and shower attach to.

Thanks

The same problem exists. You may not discharge a major fixture, (your toilet) past a unvented minor one,( the shower) The shower MUST be vented. If this is the way the plumber left you then he did a poor job. He should have connected the shower to the lavatory and be wet vented by it.
If the shower were attached to the sink or lavatory drain it would be wetvented by their vents, but it's not vented at all and your discharging a toilet past it and that could pull the trap seal right out of it. The shower MUST be vented. Regards, Tom

Thank you again for your assistance.

The house is new construction (2 years old) and this is how the builder left it. I guess I could be wrong about the shower vent since I can't actually see under the concrete. I am basically speculating based on my observations of the direction the shower drain trap is pointing (I guess it could make a turn and tie into the sink drain under the concrete, but without digging up all of the floor I am not really sure).

Since all new construction in my county is inspected am I giving too much credit to both the builder and the inspectors that it is in fact vented correctly? Should I assume its correct, or just to be safe and vent the shower anyway? If so, does it hurt anything if it is already wet vented and I re-vent it again?

Can I just tie into the already existing vent at the sink, by running a length of pipe across the ceiling, over the shower, down the wall and into the drain line? If so, where do I tie it in... before the trap or after? Thanks again.

Mark

Hi Mark,

"Since all new construction in my county is inspected am I giving to much credit to both the builder and the inspectors that it is in fact vented correctly? Should I assume its correct, or just to be safe and vent the shower anyway? If so, does it hurt anything if it is already wet vented and I re-vent it again?"

It's a big mistake to assume anything in plumbing but if the plumber knew his stuff he tied the shower into a fixtures drain line where it would be wet vented by that fixtures vent.
Since you just assumed the shower was tied into the toilets drain line it's a pretty safe bet that it wasn't. Most plumbers follow code when they rough a house. If you cancontact the builder of the plumber that did the job you might ask but if you can't I would install the shower any how. If the shower wasn't vented you could always come back on the builder/plumber for a shoddy job. Good luck, Tom

Thanks Tom... I called and left a message with the builders site manager, I'll let you know what they say.

Mark