Understanding the factors that influence internal corrosion is critical to preventing or identifying its cause and putting into motion an effective corrosion control program. This paper discusses critical water quality parameters that affect internal corrosion, identifies tools to assess internal corrosion, and discusses strategies to control internal corrosion in distribution systems and home plumbing. It focuses specifically on corrosion of metals (e.g., lead, copper, iron, etc.) and does not discuss strategies to assess or control corrosion of concrete-based materials. Includes 60 references, table, figures.