This chapter gives an overview of the various materials that are typically used in the construction of pressurized waterlines, deterioration mechanisms that can apply to each, as well as the condition assessment techniques that have been developed to detect signs or symptoms of degraded functionality. While destructive testing and visual inspection are useful, the former can be extremely expensive and time-consuming, and the latter can fail to yield enough actionable information. Thus, as buried infrastructure continues to age, regular condition assessment programs will only become more valuable. Whereas brick, reinforced concrete, and ductile iron gravity sewers can all benefit from a CCTV crawler, there is no single technology that can effectively provide useful condition assessment information for a water supply network consisting of a mixture of cast iron, ductile iron, asbestos cement, and high-density polyethylene pipes. Historically, condition assessment programs have been of secondary importance for waterlines, compared to gravity sewers.