Here are the chords used in this song

    B      F#      E       C       F      G
E------/---2---/---0---/---0---/---1--/---3---/
B---4--/---2---/---0---/---1---/---1--/---0---/
G---4--/---3---/---1---/---0---/---2--/---0---/
D---4--/---4---/---2---/---2---/---3--/---0---/
A---2--/---4---/---2---/---3---/------/---2---/
E------/---2---/---0---/-------/------/---3---/


Intro:   B  F#   E   B  F#  x2

B           F#
Long ago I don't know when
E                        B            F#
That's when they let the water flow in 
B                        F#
They said it's time, it's time to begin
E               B           F#
So they let the water flow in


B                          F#
Let the water flow, let it flow right in
E               B           F#
Come on baby, let's take a swim
B                         F#
Let the water flow, let it flow right in
E              B           F#        E     F#   back to B
Come on baby, let's take a swim in love


Verses are the same and choruses are the same.  On the key change
just insert C for B and G for F# and F for E.   Have fun even though
you probably won't have the 40 druken girls singing the last chorus
with you.  Enjoy.