Aaaargh, no, not the Medieval Bathing Myth again. I'll try and jump in about the Medieval Water Myth as well before the full wrath of /u/DanKensington is fully invoked.

HERE is an excellent post about the Medieval Water Myth by /u/DanKensington and HERE is an older but still very useful post by /u/Flubb specifically about dumping waste in the streets. The tl;dr of those posts is that medieval communities took the safety of their water supplies very seriously. The vast majority of settlements - even up to the level of towns - simply weren't densely populated enough that they could cause a significant level of water course pollution, and the population often still gathered water from wells even though there was frequently a river nearby. Nonetheless, settements very often had strict regulations and bans about people throwing waste into the streets. Of course, the presence of rules against something always suggest that to some extent people were doing The Yhing, but the often very strictly enforced rules also suggest that authorities were aware of the problems caused by The R Thing and were actively trying to fix it, and hopefully that those bans were reasonably effective. Of course, throwing your waste away was also throwing away an industrial resource that could be used in tanning.

I recently wrote an answer here about the Medieval Bathing Myth. The tl;dr of that is that medieval people still washed regularly, they just did it individually for hygiene rather than taking part in Roman style communal pseudo-ritualised bathing as a social activity. We know from a number of sources that medieval people still very much valued smelling nice.