I want to install an upright water tank in my trailer and was looking for opinions on where to put it. It would fit into either the dead space behind the saddle rack in my removeable rear tack or into the small corner of the dressing room. I want a fill port towards the top and a spigot at the bottom. I'm thinking this is going to be a pretty much permenent installation. I am also assuming that if it is mounted in the dressing room I should pull the indoor/ outdoor carpeting out from under the area before putting the tank in.  

I have never used my saddle rack in the front of the trailer (moveable from the rear) and usually just store folding chairs in that corner. I have only removed my rear tack a few times in four years of owning this trailer but it is nice to have the option to pull it out to haul things other than horses. I was also wondering if the weight of the water (25 gallons=200 lbs) would be something that would be better placed further forward than at the rear of the trailer.

Opinions please???

You have pretty much narrowed the installation down to two spots, the corners of your rear tack or your dressing room. If you want to be able to fold up the rear tack, you are left with dressing room. As you suggested, a corner is the most efficient use of the space. If you do mount the tank permanently, it would be quite easy to install an outside fill and spigot for easier access. A fabricated drain pan similar to a house hold's hot water heater or washer, would prevent the carpeting from being saturated in the event of a leak.

If your trailer is a GN, it won't really matter as far as towing, where you install the tank. If your tank is half way between your trailer tires and the hitch, aprox half of its weight will be on the towing vehicle. If it is installed in the rear tack, all of its weight will be on the trailer axles. Either way, it will not cause much to effect a change, in the way your trailer will tow.

Gard

gard - thanks for the reminder about location and weight.

I am going to sell my 30 gallon Dry Camp (saddle rack type) water caddy and purchase the 48 gallon Half Moon Upright. I plan to strap it to the left wall, where a tack compartment would be (and I don't have).  It has 2 outlets and 1 inlet. I was going to build a short support stand to raise it a little bit and also to create a "nest" for the base. The stand will also give me storage for hose.

Putting it back there will help with weight distribution since I'm towing with a F150. I used to put the 30 gallon tank in the truck bed. 8.64 x 30 gallons was quite a bit. And I was getting worried about the extra 18 gallons  (415 pounds versus the 260). Since it will be in the back part of the trailer - less worry  ... whoopee... : )