I live in a major metropolitan area in the United States, and we have a municipal recycling pick-up program. They advise us to wash food containers prior to putting them in our bins, and if an item takes "too much water" to wash, that it's better to throw it away instead. What are the differences in the ecological impact between using more water to wash-out a difficult-to-clean item (e.g. a plastic peanut butter jar) vs. throwing it away? My gut feeling was that it would objectively be better to use more water to wash an item so that it could (possibly) be recycled than it would be to conserve water and have it (ultimately) end up in a landfill, but I don't have any background to evaluate one way or the other.
Edit: I changed the title of the question in response to some answers and comments. It used to be "Is it more sustainable to save water or to recycle", which hid the assumption that I would use potable water, and which wasn't clear that I was asking about recycling waste (not water).