I don't know about anyone else’s evaporation problems but I bet I put in approx a gallon a day. Thank G I bought a RO/DI system. My original thought before I set my tank up was to get butt loads of distilled water from Costco. Glad as hell I didn't do that.
I highly recommend going to ----, and getting one of those systems. They are very easy to install. I bought the dual output system with the faucet and 4 gal tank. I run one output, through the floor, to a plastic garbage can, the other output goes to the faucet. It's used daily by my family. In my case, all I do is walk downstairs to my 35 gal reservoir and get my water. Cake.