How do you take good care of a potted cactus?

ive had cactus for years and used tap water and they lived. i like to water them once a week during the spring and summer because i keep them inside a room with a bunch of windows in my house. in the winter water them about twice a month or so. most plants dont grow during the winter, thats the dorment time. bottled water is safe for drinking. distilled water has been evaporated then all the steam is collected back into water