do NOT use distilled water ... it has all the necessary minerals removed (your plants need calcium, magnesium, iron, etc.) ... tapwater is OK, IF you let it sit for a couple days for the chlorine to dissipate ... actually, the chlorine won't hurt the plants at all, but it will kill beneficial organisms in the soil ... 'Reverse-Osmosis' water is also not the best choice, as it has the minerals removed, much like the distilled water (plus, tends to be acidic, from the absent calcium) ... be sure to pH your water, if growing in soil, it will ideally be about 6.8 ... I recommend filling bottles from a friend's well-water, usually a good source, as it still has the minerals, but not the chlorine ... I make a 40-mile roundtrip once a month, and fill my bottles from a natural spring up in the hills ... :smokin: