I'd like to pin down once and for all the infomation I'm picking up from the net about watering carnivorous plants with tap water. While I know it is bad for them and I still use filtered rain water for mine I have seen advice ranging from "It is ok now and again" to "YOU WILL TEAR APART THE FABRIC OF SPACE TIME IF YOU DO" well not that bad but have seen "Even a drop is a 100% kill for CP's". I know there are fancy filters on the market and such and even people saying to use deionised water (the type for car batteries and irons) at a push if stuck. But is tap water as a one off really that bad?