For the RO.....I have been hearing from science that RO has very little buffer capacity and shouldn't really be used in agriculture applications alone. A general guideline is to use it mixed 50/50 with regular water to improve your source water and still keep some of the buffer capacity to better control the ph of your soil. Idk if that is the case with DBHBB, but I am looking into that and waiting to hear from Doc on that subject.
The water containing lead is not from the city water, it is from the pipes connecting the old buildings to the main off the street. So any contamination is happening there. I live in an area where they say "you may have" so water testing will be done. If I do have lead, my landlord is supposed to supply a filter. The city discovered the lead issue this past summer and are forcing all buildings to upgrade by 2020.
So I will be getting a water test done and will proceed with caution. I do plan on mixing my water with RO at 50/50 to see the results first hand and also plan on doing some soil testing to see what is actually happening there. Science!