Well the clocktower has a river flowing undernearth it so i'd imagine they get their water from that, after all no point in situating a clocktower over a river unless it's a water run clock or you can multipurpose the tower, judging by the fact the washing area appears to be a continuation of this same river lend credence if not truth to the idea, we also see two shallow pools of water next to the clock tower mayhap this is where the water is leaking out.
Yeah I think that underground river is the source of Clock Town's water.
Icemelt is also viable, Snowhead more specifically around the temple is perpetually in ice and the further down the mountain the warmer so it'll melt giving fresh water to gorons and all, hell they even have a lake up there, taken a step further this could be the same source of water for the river near Zora Coast where the beaver bros live and down to clocktown and the swamps.
I disagree, I think in the lower areas it's still too cold.
One thing important to note is the gigantic water source flowing in a cave from the Goron Village's shop, meaning that, whether frozen or not, a constant stream of water will always be present from the mountains.
This flowing water has somehow stopped flowing while Gyorg is alive in the temple. It must have been unimaginably cold in order for flowing water like that to just stop flowing. Also keep in mind that the water still isn't flowing although that lower area does seem to be warmer than those higher up.
Also you know it's gotta be cold when a blacksmith's fire freezes, lol.
Speaking of swamps they could just set up a water purification still there all it needs is a container some glass and a collection pot and boom fresh water. Maybe that's what the potion shop is for.
Doesn't seem like a reliable method at all. It'd take way too long. Even the Deku probably aren't using that method.
While on the topic of the swamp, I've been wondering, if the water is poisoned further up near the Deku Palace and Woodfall, is the water lower (like near the potion shop, and the swamp tour shop) also poisoned? The water lower is just murky, it doesn't look poisoned - could the looks be decieving? Could there still be traces of poison which are harmful but not powerful enough to change the water's color down in those areas?
Or you know they barter with the zora for zora crack juice.
I don't think they have that in Termina, but it's definitely worth a SB debate.