Use the hose, buckets sux.
I've been doing it for 20+ years in a few different countries and never had an issue. I always siphon first so the old water in the hose is removed that way, but it sounds like a good idea to run the water for a while first especially if it's cooking in the sun. I also don’t treat my water, just pure tap water, cold, directly into the tank. Disgusting huh?