Unless your tapwater is unusually hard or unusual it should be fine. CFO water ok but may be too pure. Watering will depend a lot on the size of the pot the size of the plant and how warm it is how sunny it is. New soil doesn't need any fertilizer at all but actively growing plants will need fertilizing more often, especially in spring and summer. No fertilizer in winteris fine during winter they usually slow down quite a bit and need less water and fertilizer

Hi! Fluoride & lime can't evaporate, so letting water sit doesn't help eliminate those substances. Most municipalities no longer use a form of chlorination that can evaporate either. Room temp water is good, regardless of type. Distilled water has no chemical substances in it.

But Sansevieria don't seem to be sensitive to these things, in moderation, when watering thoroughly so that excess flows from the drain hole, so not a usual concern for these plants.

If I've ever fertilized one, I've forgotten, not something on my radar at all. I do repotting anytime from spring through fall.

How long have you had your plant?

woodnative: I do think our tapwater is hard. In some cases, after watering, a white frosting appears on the soil....

Tiffany: I'm considering going to distilled water. This "white frosting" can't be a sign of anything good. I've have some plants about a year.

Great job so far! If you've had them that long, any time-release fert that was in the soil should be depleted so there wouldn't be a risk of double-doing it. When repotting, note whether or not the new soil has any of that in it. If so, adding more before it's had a chance to deplete could be too much. Too much fertilizer is toxic, though some is probably better than none. I'm not anti-fert, just gun shy about it after killing a lot of plants with it in earlier times, and it always seems like a good idea to buy another plant or 2 instead of a package of fert.

The white frosting sounds like lime/calcium deposits. I've stopped seeing that on plants since I started watering thoroughly, taking plants to shower or sink, even though I use tap for all plants while they're inside during winter.