I've been experimenting with a Swiss Army surplus water bladder recently, I learned about the product from an article I posted from one of the magazines earlier in this thread so I ordered one.  Here's the original post:  
	
	
		
			
				
			
			
				
				Put a lid on the shoe bag in case it rains and some drain wholes .  I put a drain hole in the bottom of each pocket and finished the holes off with grommets:    The ARB shoe bags don't have lids either; since the bags hang under the rain fly of the tent opening lids haven't been necessary so far...
				
					
						
							 
						
					
					expeditionportal.com
				
 
			 
		 
	 
That bladder has a cap/nozzle that's not very useful for use as a water source to a sink or shower, so I modified the cap to have a quick-disconnect.  This is the nozzle as it comes, it's got a push-button valve on it and a spout that doesn't lend itself to attaching a hose:
	
	
	
		
		
		
		
	
	
Modified, the stock spout and valve is removed and replaced with a quick-disconnect fitting:
	
	
	
		
		
		
		
	
	
	
	
	
		
		
		
		
	
	
In action:
The water flow is very good but I thought it would be a bit more satisfying shower if it had more pressure.  I've been working on a solution, I posted about it yesterday: 
https://expeditionportal.com/forum/...factory-hardtops.127687/page-310#post-2898885
Another water bladder was recently featured in the magazine:
	
	
	
		
		
		
		
	
	
At about 7 gallons, it's a little longer than the Swiss Army surplus one I've been experimenting with.  Here's a link: 
https://www.frontrunneroutfitters.com/en/us/water-bladder-27l-kit-bag-plus-inner.html
Seems like it would make a good warm water source for a shower (or warm water for washing dishes?).  If there's extra room on a roof rack, a simple tray with some straps would make a good place for it.  Some concept images:
	
	
	
		
		
		
		
	
	
	
	
	
		
		
		
		
	
	
When full it would weight 59 lbs., that weight up top could be a consideration for some Jeeps.