Main cause of lead contamination in drinking water is?

• A. Chlorination byproducts
• B. Lead containing materials in household plumbing
• C. Bacteria in the water
• D. Plastic pipes

Answer: (B)

Lead in drinking water mainly comes from materials in the home’s plumbing that contain lead, such as old lead service lines, lead-containing solder, and certain brass fittings. Water can dissolve small amounts of lead from these components, especially if the water is corrosive (low pH or low alkalinity) or sits in the pipes for a long time. That’s why older houses are at higher risk and why corrosion control or replacing lead-containing parts is an effective way to reduce exposure.

Chlorination byproducts, while important to monitor for other reasons, are not sources of lead. Bacteria in water relate to microbial contamination, not lead. Plastic pipes themselves usually don’t contain lead, though connections in older systems could include lead-containing materials. So the main cause of lead contamination is the presence of lead in household plumbing.