We do have giardia in some of the streams here in Western USA. I have a little pump filter that I take backpacking. It is lighter than taking a bunch of water.

I can usually carry enough water for a day trip, but would carry the filter for an overnight trip. However, I have been known to just get a cup of water out of what appears to be a fast flowing small, fresh water stream.

Giardia, of course, has a long incubation period, so you won't know until long after one is back home.