Not unless it is sea water.
Normal water won't cut it, only that of the sea.
And besides, won't kill Eneru, survived Sea Stone, then a Reject Dial(which blew a beanstalk in half that a giant 300 foot snake could barely budge, and this was after two of the stalks were already cut in half).
Hell, even survived being plunged in the sea.
These are some of Eneru's capabilities without using lightning as a means of offense.
http://www.onemanga.com/One_Piece/280/04/
http://www.onemanga.com/One_Piece/280/05/
http://www.onemanga.com/One_Piece/280/06/
http://www.onemanga.com/One_Piece/280/07/
http://www.onemanga.com/One_Piece/280/08/
http://www.onemanga.com/One_Piece/280/09/
http://www.onemanga.com/One_Piece/280/10/
http://www.onemanga.com/One_Piece/280/11/
http://www.onemanga.com/One_Piece/280/12/
http://www.onemanga.com/One_Piece/280/13/
http://www.onemanga.com/One_Piece/280/14/
As you can see from those scans, Eneru easily predicted Luffy's attacks.
Also, we see his strength and speed when he casually catches Luffy's fists during Luffy's Gomu Gomu Gattling Gun attack, which is so fast it makes Luffy appear to have multiple arms. Luffy is also strong enough to throw a 100 ton or more sea cow(and I mean that literally) miles away, and kills giant sea kings with single punches.
He also shows skill in wielding his staff.
He can manipulate metal as well, and fashion it into weapons.
Also, for lulz:
Originally posted by Dark-Jaxx
When?
In the SBS (question and answer poll in shounen jump)
http://www.arlongpark.net/Manga/SBS?highlight=(sbs)
Here, I can't find the exact quote but it's on one of these pages somewhere
Dude, I just read through pages, and did not find shit, and don't feel like reading more, but one thing I did however find...
"D: Oda-sensei. Since Luffy is a Gomu Human, does that mean his "p*nis" can stretch, too?
O: His penis can stretch too. "
ROFL
Also, EM, what is your opinion on the actual fight?