How Lead Gets Into Household Water (Pipes, Fixtures, Solder, Brass)

Lead contamination in household water is almost always the result of legacy plumbing materials interacting with water chemistry. Lead pipes were widely installed through the early 20th century, and even after they were phased out, lead-bearing solder and brass fixtures remained common until the 1986 Safe Drinking Water Act revisions. The problem is not that these components “shed” lead continuously, but that time, temperature, and corrosive water conditions accelerate microscopic leaching at the metal–water interface.

Inside older plumbing, water can dissolve lead particles through a process called corrosion scaling. When minerals in the water become unbalanced—low pH, low alkalinity, or high chlorides—the protective layer on pipes breaks down. This exposes lead surfaces to the water first thing in the morning or after long periods of stagnation. Even plumbing labeled “lead-free” prior to 2014 could legally contain up to 8% lead, and those brass components can still release detectable levels into home water supplies.

Lead can enter water from:

• Lead service lines connecting the home to the water main
• Solder joints used in copper piping prior to 1986
• Brass fixtures, valves, and faucets manufactured before stricter regulations
• Corroding galvanized steel pipes, which can trap lead from past systems and later release it

Because lead does not degrade, any home with older materials has at least some potential for leaching. The only way to identify actual exposure is through testing. A sensitive lead-in-water screening test can determine whether your plumbing is contributing detectable lead.

By A. Anagnos, Biomedical Engineering Specialist