When backpacking in a coastal region, you sometimes have access to both fresh water (e.g. a stream) and salt water (sea, bay, etc.).
If you do not treat the water used for washing dishes, what are the pros and cons of using saltwater vs. freshwater? Is there one source that is less prone to contamination?
The choice is easy if the shoreline is polluted or the stream is next to a privy (established or... improvised). However, when there are no obvious differences in water quality, which one would be more recommended and why?