Pete, my four pennies worth... been using a 66 litre water tank in my 90 which fits between wheelboxes against bulkhead out of the way, (got a plastics company to make it)spares parts, oils etc and tools are then put in and a sheet of 2mm alloy chequer plate over the top of it - bolted to wheelboxes - fridge/cooker/cooking/food boxes and chairs/table etc above this.
feed to tank is from a pipe inside the back door (which runs along the side of the vehicle and into the top of the tank - a vent pipe also runs alongside) - which I can fillby hose pipe or put a funnel into and fill by bucket - so it is filled by gravity. I was going to put a marine alloy water filler on the side of the vehicle, but this works well and can be removed easily -and is secure when the door is closed.
the feed from tank pipe runs straight out the left lower side to the back door with a 90 degree plumbing 'tap' valve, on the rear x member is a small alloy loop which the tap sits in so you can open the rear door put the tap in to the loop and turn it with one hand - handy after doing a service and you are oily - again gravity fed. use blue water pipe -clear pipe will get algae growing in it.
bad water ? - just dont put bad water into the tank ! - a smell then if it smells ok, a taste and spit (and rinse mouth with fresh) to see if it is drinkable before filling
then use katadyn micropur powder- keeps the water fresh for up to 6 months.
If you are unsure of water quality then use the correct number of drops of iodine/litre
as a back up.
the 90 is quite limited for space and this works better for me than carrying 3/4x jerrycans - it also keeps the weight down low and central on the vehicle.
I do carry a 20 litre water bag too, for showers and longer trip legs.
youve got plenty of space in the 110 so jerries are cheaper (and easier) - the in jerrcan pump would work well.
If you want a photo of the tank let me know.
the gravity fed tanks and micropur work - I used them on overland trucks with 350 litre tanks and paying passengers all around the world.
[This message has been edited by Gipper (edited 25 August 2005).]