Do you like drinking hard water? Probably not, same with orchids. Water quality is one of the most important factors in growing orchids. So what would be the ideal water for orchids? The answer is rainwater because of rainwater results from evaporated water. It has no minerals or dissolved salt content. Having no minerals in the water is not great news, but it is a good starting point. That means now you can add all the nutrients in the water that is required for the Orchid plant without increasing the hardness or total dissolved salt (TDS) to unacceptable levels.
For those of you, who cannot harvest and store rainwater the next alternative is reverse osmosis water or distilled water. Reverse osmosis is not the same as softened water. Softened water would kill your orchids. That is because softener replaces the calcium and magnesium in the water with sodium which is toxic to orchids if given in higher levels.
Generally, the bore well water or groundwater is hard water and you will find that misting/ watering with it will eventually cause a white build-up on the leaves which is not only unsightly but also clog the pores on the leaves and reduce perspiration.