Addition Plumbing System. Need Advice

[JERRY500]

I am building an addition to my home and need some advice. attached is a drawing I made. Please advise me of any changes that need to be made.

[hj]

Normally, you would submit the drawing with your plans to the building department and they would either accept or refuse it. That layout would not pass here without additional vents and the double lavatory setup would be less than desirable. And the CW is not complete.

[hhplumbing]

i agree with hj,

the cw, wc, shwr and tub are not vented to code requirements

[Terry]

Every plumbing fixture there needs a vent.
I also notice that the lavs are in a corner, so each lav will need a vent there too.
I have seen layouts like yours where the lavs face each other in such a way as only one person can use a lav at a time.
When you place people in front of the lav (sinks) they will be fighting for elbow space. It's more like a single workperson stations. A bowl for the left and a bowl for the right hand. Certainly not for two people at once.

Here is a nice link to Bert Polk's plumbing tips