This is not recommended. You don't want to take the risk of using untreated water from a lake, pond, or stream. The utensils you use for cooking and eating need to be properly cleaned, dried, and sanitized so that you don't end up with an avoidable illness. Giardia is not a fun thing to experience and it may not take just drinking unpurified water to get it, but by just cleaning your dishes with untreated water you're leaving yourself open to the risk. Don't trick yourself into thinking that just because you're using soap, will miraculously mean everything will be clean and fine. You never know the bacteria that could be in a water source. Be smart and be safe!