Dishwasher waste

[LeedsRhinos]

If I plan to tee into my sink waste pipe for a new dishwasher can I tee below the trap or will that cause smells to get into the dishwasher. We are on a septic tank system if that makes a differance?

Thanks in advance for any help

[Clanad]

The tee must go above the trap.  As you've indicated, that's the only thing between you and the gasses from the septic system.  Alternately, you could install yet another gooseneck trap to serve the dishwasher.  This could then be teed into the existing one below the current trap...