Pls review my bsmt bathroom plumbing plan

http://www.putfile.com/abrahuang/images/52761

I am putting a new bathroom in the basement and replacing cast ion pipes as well. The new sewer come in through foundation 2' below ground. It will serve an existing bathroom 1st floor and the new bathroom in basement, and is reserved for laundry and morning kitchen as well. Before I glue down the pipes and call for inspection, I'd like to beg for a review here see if anything violets the IPC2006 or could work better in other ways.

On the left is furnace and water heater(do I need a floor drain or other types drain to collect condensate if a AC installed?). On the right is the cement wall. A 4" wetwall is going to be put up between the backwater valve and the bath drain to accommodate all pipes.
The toilet and left-hand bath are set side by side within the 62" room. The bath is 27" Wide, plus 2" framing on both sides, leaves 30" for the toilet. The depth of the bath is 54", so will not block the window above the vanity.
The bath requires 8" rough-in, so a reducing TY was put next to the valve, tilted 45 degree. (The bath was claimed for "above floor plumbing", what does that mean to me?) I assume a trap will connect down to the TY and in another way goes parallel back to collect the down overflow before goes into the wet wall for 2" venting.
The toilet has 12" rough in, but the reducing Y 4x3 stretched it more than 12" from wetwall. So a 90 elbow was tilted backwards, and connected to a 45 elbow to bring it plumb. A 2" vent was inserted in the 3" portion though the critical distance is less than 6', considering there is a valve in between that probably will block the air flow. I was quite unsure about this portion, whether the flow direction can loop backwards, or the nearly 2' of 4" pipe after the 3" portion is good, or the vent is too close to closet?
Pls help me out. I appreciate any opinion.

Normally, the toilet plumbing with it's larger pipe and fittings would be more important to line up, the other fixtures are easier to fit in after the fact.

The tub can be vented within 42" of the trap,
The toilets within 72"

Vents can be tied back together at 42" or higher


If you vent off of the horizontal line, most inspectors would like to see a wye fitting, not a santee.

Terry said:

Normally, the toilet plumbing with it's larger pipe and fittings would be more important to line up, the other fixtures are easier to fit in after the fact.

The tub can be vented within 42" of the trap,
The toilets within 72"

Vents can be tied back together at 42" or higher

If you vent off of the horizontal line, most inspectors would like to see a wye fitting, not a santee.

Click to expand...

I will change the T to a Y. Thanks for pointing out.
The 4" pipe will extend 20 feet along the wall to the laundry(vanity is on the way), so I will keep it straight and close to the wall.
Since there is a backwater valve, I thought the toilet and tub could be poorly vented because of the valve flapper, so I put aux vent hoping it helps. Is there any other requirements in Code when a valve is introduced?

the backwater valve needs to be accessible.

http://img2.putfile.com/main/6/16309001785.jpg

Here is the update. I will use the toilet vent for tub drain.
The valve will be accessible through a 8" tube with lid. Thanks for reminder.
How does it look this time?

drains

That looks good, but I hope you know EXACTLY how the tub is going to be connected or you will create a major problem for yourself.

hj said:

That looks good, but I hope you know EXACTLY how the tub is going to be connected or you will create a major problem for yourself.

Click to expand...

I connected the drain for tub, by a reducing T and 1 1/2" pipe. The distance from drain to vent is 33". The height can be adjusted above or under ground. The P-trap will be probably need a pit in the cement slab. I haven't seen the real tub yet, it will need 3 weeks to arrive. Does this look good? do I need a cleanout at the 1 1/2" 90 elbow?