Some RV's have a gravity fill for fresh water, but many of the newer ones like ours require a pressure source to fill the fresh water. It creates a challenge when dry camping.
Have seen signs at some Campgrounds that specifically state that you can not connect to a faucet to full fresh water tanks. Perhaps because of the bottle necks it creates where people are blocking the road.
I have one of those water thief things that I use if there are no threads on the faucet. Picky about the water we put in our tank so I generally don't get water at gas stations.
Options when you can't connect to a pressurized water source:
1. Use the input where you put RV antifreeze in your lines. Just put the line in a bucket and turn on the pump.
2. Purchase an inexpensive 12v water pump and connect between fresh water input and a container.
3. I'm looking for a hand pump that could be used. Not sure if this would work but would like to try it. Has anyone else done this?
We travel with fresh water at least 2/3 full. I drink water from our fresh water system and use it for coffee, cooking, etc. If we are getting low on water I start filling a gallon jug of water from campground water source if water is of good quality. DW prefers bottled water to drink so we usually have a couple of gallon water containers around.
We have a filter on the cold water at the kitchen sink, have considered one of those filters that go in-line with your water hose. May try one of those in the future.