if you have a forced air heating system and it happens to be 90+ efficient fossil fuel burning, it will produce condensation right at the furnace. This is usually pumped into the sewer, but you can instead pump it into a water collector (I use a 10gal Igloo cooler with a drain hole at the top and an overflow that goes into a second little furnace pump). The water produced is effectively distilled water, as it comes from steam inside the PVC exhaust pipe. This solution is specific to 90+ % efficient fossil fuel based furnaces, but it works very well. You can also use the water for plants, in your iron, etc, as it has no chlorine and no minerals. — Mark, in PA