Bathroom Sink

Our bathroom sink doesn\\\'t drain the water.

I\\\'ve used all the methods to verfiy if there\\\'s a clog (ie. baking soda/vingear, plunger,snake, nothing in trap, etc)

I think there\\\'s a vent(air)problem since when I run water with a hose directly into the pipe in the wall, there\\\'s no backup and the water can be heard draining into the main pipe. All other sinks & tubs run smooth in the rooms.

Where does it get it\\\'s air to drain the water ??

Thanks

DO you mean that it doesn't drain, or that it does but it's slow?
If it's slow, what's the diameter of the pipe and its length and gradient? I doubt venting has much to do with it if it's fairly short before getting to a large pipe or open hopper/gully.