Internal corrosion is occasioned by the combined effects and severity of four modes of material deterioration, namely: general corrosion, pitting corrosion, microbial corrosion, and fluid corrosivity. The same principals of external corrosion control can be applied to internal corrosion but due to accessibility, the approaches can be different.  Thus special instruments for internal corrosion control and inspection are used that are not used in external corrosion control.  Video scoping of pipes and high tech smart pigs are used for internal inspections.  The smart pigs can be inserted into a pipe system at one point and "caught" far down the line. The use of corrosion inhibitors, material selection, and internal coatings are mainly used to control corrosion in piping while anodes along with coatings are used to control corrosion in tanks.
Internal corrosion challenges apply to the following amongst others: Water pipes; Gas pipes; Oil pipes and Water tank reservoirs.