i assume you will be going home to pick up another 25ltr water butt when they run out? as 25 ltrs will do about 3-4 houses if tops only, if these details are correct then i would say a trolley system would be ideal for you, you could ofcourse make a trolley system that could carry 2 water butts (50ltrs in total) that would save you walking home so often, wish my round was all within 2 mins distance