When we are boondocking, our water in the trailer tank lasts about a week. On longer trips I carry two fresh water 5-gallon cans for backup. It is quite convenient to have the water in the trailer tank, but pouring from a 5-gallon can into the tank filler is quite difficult as my cans have no spout. I have siphoned using our fresh water hose, but I now have a better solution. I purchased a Lisle 17232 Right Angle Funnel for $12. These are available at various auto supply places, but I got mine off Amazon. The funnel comes with two angled bends in it for getting to awkward places. I cut the funnel just above the lower bend and it now goes into the tank filler and provides a perfect entry for dumping my water can into.