pellaz saidi would wonder what the worms are feeding on?
every city has its bad:
Denver has long since lost where the lead water mains are.
Denver has no lead water mains. Also the city does not track plumbing to individual homes. That is the homeowner's responsibility.
"Since lead is not present in Denver Water’s public water system, the major source is corrosion in your home’s internal plumbing system. In Denver Water’s experience, the homes and buildings constructed in the mid-1950s or earlier are most likely to have lead service lines connecting the building to the public water system." - http://www.denverwater.org/WaterQuality/WaterSafety/LeadCopper/LeadFAQs/Plumbing/