S.H.
Here's some basic info for you:
http://www.cdc.gov/healthywater/drinking/private/wells/di...
Sounds like... a real legal issue.... as well as health.
It has probably been going on for a long time....
Lead leaching into water/water sources... can come from a variety of sources....environmental/household pipes or soldering/water catchment/if it is artesian water or well water or rain/private wells/etc.... really, a variety of sources....
Call your Pediatrician and buy bottled water... and no, boiling water will NOT get rid of lead in it.