Gray Water Tank - Venting

Hello everyone!
 
I am getting ready to install my Gray water tank.
 
Do I need 2 holes in the top of my tank. One being a vent and one to the P traps or can I use one hole venting on top of the sanitary tee?
 
This is what I would like to do.
 
One hole:

Thank you
 
Randall

Attached Image(s)

You need to ask YOUR HD their requirements on this.

chefbuba


You need to ask YOUR HD their requirements on this.

Actually I was given our county Plumbing inspectors number last week so thats pretty good advice and will save me doing whatever I am doing twice.
 
Thanks

Hey, when I installed the plumbing on my truck I added a vent a vent after the p trap and right before the check valve aka backflow connection. I have smooth flow of water going into the tank. My gray water tank has 3-3/8inch female connections, I removed the top cap to vent the tank. Hope this helped. My thread is yet another food truck. If u wanna see pictures.

When I built the trailer I found that the mech vent under the sink cabinet was not enough and the tank was getting airlocked even though technically it shouldn't have according to a licensed plumber. I ended up running a 1/2" pipe from the top of the tank up into the wall of the unit and through the roof with a couple elbows so rain would not get into the pipe.
 
Let it breathe.

Mine is vented through the roof with 1 1/2" pipe.....Flows like a river when I open the dump valve.