Drop D 
E---------------------------)-----------------------------
B---------------------------)-----------------------------
G---------------------------)-----------------------------
D------0-----0-----0-----0--)-----0-----0-----0-----0-----
A-3h5-----5-----5-----5-----)3h5-----5-----5-----5--------
D---0-----------------------)--4-----------5--------------
       ^^^^^^^^^^^^^^^^^^^
   Repeat this several times
   its very simple, 
   just listen to the song.

Once or twice he does this near the end
E--------------------------------------------------------
B--------------------------------------------------------
G--4-4-4-4-4-4-4-----------------------------------------
D--4-4-4-4-4-4-4--0-5--5-5-5-5-5-------------------------
A--2-2-2-2-2-2-2--0-5--5-5-5-5-5-------------------------
D-----------------0-5--5-5-5-5-5-------------------------

Jam at the end switches between these two chords: You can play around 
with it, but this is basically it.

(DADGBE)   057755  and   557785

*NOTE*  Bartender and Don't Drink the Water use the exact same chords.
IF you can play one, you can play the other.