Thats sorta crazy for just lead solder. City water? What is the ph? Cause most of the city systems run the ph slightly basic to assure the water isn't trying to etch the pipes, and that also keeps the lead from leaching. That was actually the problem in flint, they let the water system ph get to low and it started to leach out of the pipes which is why originally they denied there was a problem (testing the water at the source).