I saw you mentioned Maine coastline. Maine has a lot of mineral deposits up and down the coast, and I know of at least one zinc/lead mine.

The metal content is probably because the water is acidic and leaching the natural metals. If that’s the case, redrilling a well won’t give you any benefit. You’d definitely want a filter system anywhere on the coast, and reverse osmosis would make the water taste a hell of a lot better too. (Unless you like that brackish tasting water)