I like to use my tank water. We only hold 30 gallons of fresh water BUT we also use this water for brushing teeth, the dog's water and for making coffee. So by us using the water in the tank I know it's just as fresh as the stuff coming out of the hose. Part of our pre-launch precedures is to top off the water tank while waiting for the engines to warm up. Depending on what we are doing on a weekend we will top off the fresh water 1-2 times per weekend so that means when we leave on Sunday there is little to no water left and then we top off on Friday when we get to the boat.