What primary issue does lead pipes pose to water distribution?

Lead pipes primarily pose a significant health risk due to the potential for lead contamination in drinking water. When water flows through lead pipes, especially if the water is slightly acidic or has low mineral content, small amounts of lead can leach into the water supply. Consuming lead-contaminated water can lead to severe health issues, including developmental problems in children and various health issues in adults, such as hypertension and kidney damage.

While it is true that lead pipes may contribute to some level of corrosion, the foremost concern is the direct impact on human health from lead exposure. Other issues such as hardness and taste may be related to different types of piping or water chemistry but do not represent the primary concern associated with lead pipes. Therefore, the correct choice highlights the critical health implications of lead exposure from contaminated water.