I am doing a contest and the riddle is "We're clear on which is which.
 Now tell us where they are.  (refer to photo)"  I can't show you the
photo, but it is a picture of two water towers, one is skinny and tall
and says "HOT" and the other is next to it and says "COLD".  I need to
find out where they are.

I hope I'm not stepping on any toes by posting my 'comment' for you...
I was actually doing a bit of research myself and stumbled across this
question. But here is what I think you are looking for:

"Pratt, Kansas - Hot and cold water available" 
http://www.roadsideamerica.com/attract/KSPRAwatertowers.html

I found this on Google by searching for 

+hot +cold +water +tower

I'm sure there was an easier way, but that is how I came across it
this time.  There is even a picture of the two water towers that you
can check out, just to be sure.  If you've got the same picture I do,
then this is what you're looking for.

Hope this at least helps.
Trea

I actually have this answer but don't know how to give a answer.  Do you?

As a note to lkggurl, only Google Answer Researchers provide offical
answers to questions, though often times, commentors will provide
assitance via the "Post Comment Feature", similar to what Trea did.

Ok, well I am also in this contest and I am almsot done so I do have
that answer.  Yes it's Pratt, Kansas.  Though there are lots of them
around, the picture matches.

The ones in Kansas are not alone. There are actually a lot of these. 

CANTON KANSAS
http://skyways.lib.ks.us/towns/Canton/images/wtowers.jpg

BOWIE TEXAS
http://www.city-data.com/picfiles/pic818.php

PRATT KANSAS
http://www.angelfire.com/ks2/prattrecords/images/hot___cold2.jpg

CLINCHFIELD KENTUCKY
http://www.wiringfordcc.com/95h02519.gif

OKEMAH OKLAHOMA
http://www.metalbox.net/images/hot&cold.jpg

tutuzdad-ga

There are actually sets similar to those shown that I found on two
websites in Clear Lake, Washington.  Also if it is a normal riddle
they usually put a spin to it like "were CLEAR on which is which" and
the CLEAR lake, WA.  Maybe there are multiple set that look the same. 
I don't know though I don't have your actual photo to refer to.  The
links are:
http://www.platinum-aerial-images.com/scenic.aspx and at
http://www.studentwarehouse.com/classifieds/adDetail.asp?cat_id=34&sub_id=130&ad_id=105
it is that whole long link.  I hope this helps.