I am reworking my master bath and will not have a convenient location to vent my bath tub. I understand that if the bath waste pipe goes directly into the waste stack that it is considered wet and does not need to be vented. Is my understanding correct? If yes and pipes are not exposed, what is the easiest way for me to determine if my waste pipe is wet? If I am unable to determine if I have a wet vent, or if I do not have a wet vent, then the nearest vent location is roughly 8 feet downstream. Are there any issues with venting 8 feet downstream?

Thanks

Adam

If your waste stack is dry,( nothing draining from above) it then becomes a vent stack and you may discharge the tub into it.
The inspector will call you on a 2" drain that's 8 feet from trap to vent and growler will be unhappy but if you're not going to get it inspected then go for it.
As a rule we wet vent out tubs by connecting the tub drain into the lavatory drain. Good lick, Tom