Our house is over 100 years old. All the plumbing has been changed out. It's a smaller house with a single basement, so it probably wasn't too difficult.
We have a drilled well too. Ours was/is contaminated with some stuff too. There use to be gas or oil floating on the surface straight out of the well. We have always filtered our water since we bought it back in 1997. A lot of rural wells have some type of contamination. Everyone in my opinion should be running their drinking water through a reverse osmosis, even in the city. They will remove lead as well.