Large parts of Stockholm is (as many major cities are) old industrial land. The heavy metals and poisons eill unfortunately keep polluting for s long time still. Worse, the heavy metals don&#x27;t count in most &quot;water quality&quot; measures, such as when grading water for swimming.<p>Still, the water in central Stockholm is much better than in many comparable <i>cities</i>. That doesn&#x27;t mean it isn&#x27;t bad compared to a non-major-city body of water, but it&#x27;s very good by those standards. The standard &quot;very good&quot; here means fish and other wildlife is doing alright, and swimming is ok.<p>I think Swedish drinking water is usually excellent, although it&#x27;s a lot worse in the major cities (where most people live).