The decision to water it right away depends on your circumstance and the water status of your particular orchid. If the pot "feels" heavy or the medium is damp or wet to the touch, or if you put a wooden pencil or chopstick in the medium and it comes out damp or with little bits of the media sticking to it then no do not water right away.
If the pot feels light, and very dry and the medium is dry as well then yes, water it right away.
If you have softened water you need to use bottled water. If you have a lot of chlorine in your tap water then you might consider boiling the water first and then waiting until the water is COMPLETELY cool before you water it.
If you are new to Phalaenopsis (or even if you just need a good reminder about Phalaenopsis and orchids in general go to these pages on my web site and read them. Perhaps consider printing them as there is a lot of really good information there.
For Orchids in General:
http://www.orchids-plus-more.com/frequently-asked-questions.html
For Phalaenopsis Orchids in particular:
http://www.orchids-plus-more.com/phalaenopsis-orchid-care.html
If these links are not clickable then copy and paste them in your browser and hit Enter.