acidic water can leach some metals from ground, so maybe that’s what’s going on. in that case there might be no lead in pipes and it’ll still get in water because it got there before touching piping

maybe they have no idea. do you live near mines?

maybe you can make ion exchange filter work. remember to maintain it regularly and test water for lead content after filter is installed to make sure it works. ion exchange resins work best if water flow through them is slow