Partial sources of lead in drinking water systems may include?

• A. Lead service lines, interior housing, plumbing especially where solder is used
• B. Goose necks or pigtails
• C. Private water wells or plumbing equipment
• D. Water mains / rarely

Answer: (A)

Lead can enter drinking water mainly through materials that water comes into contact with inside the plumbing system. The most common partial sources are the service line that brings water from the utility to the home and the interior plumbing inside the house, especially where solder or fittings containing lead were used. Water sitting in contact with these lead-bearing materials can dissolve lead and carry it into the taps, which is why replacing or treating these sources is crucial for reducing exposure. Goose necks or pigtails are specific interior plumbing parts that can contribute if they contain lead-containing solder, but they fall under the broader interior plumbing category. Private wells and water mains are less consistently sources across typical systems, making them less representative of partial sources in general.