Venting ?

I'm remodeling some bathrooms in a house that I bought. Taking a Hollywood bathroom and making it into 2 full baths (master/2nd) with use of adjoining closet space. I know how to do plumbing for all parts except the vents. That's a concept that I'm unsure of. At the present time I have the Main 3'' vent/drain line (out of foundation) running up the middle of the new master bathroom I need to move that to a wall and make it a 2'' (to fit in wall) vent. There is also another one that is in the middle of the master bathroom that comes out of the foundation 2'' that needs to be moved (this one attached to no drains).

I think that these can be moved and it does not matter if they are straight up or not. Are bends in the vents 45, 90s etc OK?

Do I need a vent going up at every shower drain, toilet drain and sink drain? Or can i just tie them in below to the main from basement. I had a person telling me that it would be ok to tie into the main and i did not need vents at every drain point (sinks, showers, toilets). I thought that every drain needed a vent coming off of it so the drain would drain properly.

I was basically going to run a vent pipe up to attic and tie to main.... running vents from the two tubs (master/2nd), the master shower, the single sinks in each bath and vents from the toilets up.

So, 5 vents up and then if I add one for each toilet...... the total vents running up would be 7 that tie into each other or to the main eventually.

Basically i thought when water went down air had to go up.

Maybe a little to detailed in the explanation. I may just need a simple answer to what has to have a vent off of it and what does not.

Thanks for the help

If you don't understand venting, then you really don't understand plumbing. Every trap needs a vent. Some codes and AHJ's allow wet venting. The individual vents need to run vertically to a point 6" above the flood rim of the highest fixture, then they can run horizontally and be tied together, with a proper sized stack continuing vertically.

Thanks for the reply. I vented ever line that is going to have a trap and tied them into the main vent out the roof.

How they are vented and the distance from the trap to vent also is important. The types of fittings used and pipe size is also.

vents

HAVING a vent and having a CORRECT vent can be two different things. If you didn't know what to vent, then I would be concerned that you did not know how to vent them. "Water goes down and air goes up" is like "Water goes downhill and payday is Friday". They both give the essence but leave out a lot of details.