Looking to finally plumb in my GS3 and would like some recommendations for a good water filter. I'm really sick of lugging spring water back and forth from the grocery store!
I live in Longmont, Colorado and apparently our water is pretty hard??

Also, I take my GS3 to random events once a week so I need to come up with a good way to quickly disconnect and reconnect it from the water line?

Any suggestions would be greatly appreciated!

Take a look at Chris' Coffee Service. They have a very easy to install setup that wont break the bank. You'd want the one that includes the softening, not just the single stage filter (that's what I have).

Also search previous discussions, e.g., "water filtration for plumbed in espresso machine" and matches like Plumb-in options for La Marzocco GS/3. I wouldn't recommend quick connect plumbing fittings like John Guest/Watts since they are not designed with lots of disconnects/reconnects in mind; searching on "plumbing metal quick connect" looked promising, e.g., freshwatersystems.com - LC Series Chrome-Plated Brass Couplings.