Gas line : does it need to be sterilized?

I'm reading websites and I'm viewing videos where people show how to wash kegs, but they never wash their gas line. I was wondering if it's necessary to do so?

I'm asking this because I would like to use the same gas line for my keg full of beer, and sometimes use it to produce sparkling water (which doesn't required the same PSI). So, do I need to wash it every time I want to reconnect it to the keg?