system
Given the following post, respond as if you're commenting on Reddit:
human
Why are astronomers always looking for water?  

Isn't it possible that some sort of E.T. could evolve to live off of some other sort of other element?  I mean I know that water is a safe bet but shouldn't we widen our horizons.
gpt
Two part answer:

1) Water has a number of unique properties, which are very useful to life on Earth. It is an excellent solvent, as well as a good middle point between acids and bases. It is strongly dipolar, so it is easy to move around tubes. 

2) There isn't anything fundamental about it, though, that means it is necessary for any replicating molecule. But, when searching for ET life, you need to start somewhere. Like omgdonorkebab says, we may as well look for things that we know can exist.