How critical is water type?

[AmandaTom]

Hi all
I have been growing orchids for about 3 years and water them with water straight out of the tap. Where I live, the water is very hard. I soak the plants as needed--about once every couple of weeks depending on type. I recently read that RO water can make a huge difference. Does it?

I have stans, bulbos, dendros, catts, and oncids, most of which actually bloom. I haven't killed a plant yet.....

Thanks!