Even if your main pipes are copper, the brass faucets and valves in your home can contain a small percentage of lead. Brass is a zinc-copper alloy, and lead is often added to make it easier to machine. Modern “lead-free” brass is now common, but older fixtures (pre-2014) might still leak trace amounts.
Then there’s solder—that shiny silver stuff that joins pipes together. Before 1986, many plumbers used 50/50 tin-lead solder. Each joint is like a tiny lead reservoir. Water flowing over those joints can pick up particles, especially if the water is acidic.
