It shouldn't be that hard to track at all with a little brainpower. When did we stop using lead and iron piping? Add another 10 years forward and start from that date back, and find every home matching the age/time range.
Everything else should be copper and/or plastic.
Edit: Another consideration - I'm not sure, but I wouldn't be surprised if there was a "lead scale" like with lime or calcium which could even hang around in "good" copper pipes. Someone more familiar with chemistry or water/wastewater engineering could probably give a more educated answer.
Who says we stopped? Water mains often have service life > 100 years. Old buildings have old plumbing.
My guess is they do have (some) data, but it's split among departments, in different formats. Assuming detailed records were kept that far back.
You'd assume I'm an armchair analyst instead of someone that actually does civil planning work.
They have ALL of that data. It's in the damned city plats. Go pay $20 and get a copy of your neighborhood's electrical and piping. Hell you can actually look it up for free online using ARCGIS.
http://www.arcgis.com/home/webmap/viewer.html?webmap=1aae14d...