A cured-in-place-pipe (CIPP) liner inspection system used to inspect a resin level in a CIPP liner that has been impregnated with resin using an inspection chamber having an optical sensor. The CIPP liner inspection system is also used to identify zones within an installed CIPP liner having lower mechanical strength due to inadequate distribution of resin using a robotic unit having an optical sensor. The optical sensor measures an optical property, which is used to determine a resin level or a mechanical property based on predetermined correlations between the optical property and the resin level and predetermined correlations between the optical property and the mechanical property.