Decades after the dangers of lead became clear, some cities are leaving lead pipe in the ground

Prandy Tavarez and his wife were expecting a baby when they bought a four-bedroom house in a well-kept neighborhood of century-old homes here. They got to work making it theirs, ripping off wallpaper, upgrading the electrical and replacing windows coated in paint that contained lead, a potent neurotoxin that can damage brain development in children.

That wasn’t the only lead. The pipe carrying water to their home was made of it, too. Providence’s tap water had had dangerous lead levels for years. So it wasn’t surprising in 2008 when a...