You have a good choice on your side of the Lake, 3 clubs Horgen, Waedenswil and a bit further in Thawil.
http://www.seeclubwaedi.ch/index.php?id=60 this is the link for the contact at waedenswil, they row on a Thursday evening and a sunday morning (for the general "Breitensport" group).
Thalwil rows on a Thursday evening and saturday morning , again "Breitensport"
http://www.rcthawil.ch rct@rcthawil.ch
and finally Horgen is at

and homepage is
http://www.seeclub-horgen.ch/
All clubs will have a "breitensport" section "general public" section as well as the serious "Leistungsport" or "professional" ie competitive section. So irrespective of your level from beginner to professional competitor the clubs should be able to cater for you. Most clubs also do "induction" courses. These are great if you are new to rowing. Firstly you learn all the stuff in German, plus you join with a group of people of all the same level so you can already make some new contacts within the club rather than just turning up as the sole new person in^the village.
Good luck, maybe we should start an EF rowing team soon!