If you're in a remote location, finding good sources of water can be a challenge. A water filtration system like this GravityWorks is pretty amazing because it will filter 4 liters of water in just over 2 minutes. No pumping required.
The filtration system uses gravity to pull the dirty water through the filter into the (lower hanging) clean bag.
The filter meets all EPA & NSF guidelines for removing bacteria (99.9999%), and can be used to filter up to nearly 400 gallons of water in its lifetime. The water is clean, taste free and BPA-free. It's field cleanable by simply backflushing for 4 seconds.