Distribution System Corrosion: Monitoring and Control - Public Water Systems - page 711

Material Corrosion Type Tap Water Quality Deterioration

Cement Based
Asbestos-cement*
Concrete
Cement mortar†

Uniform corrosion Calcium dissolution. Increased pH values (up to 12). For asbestos-

cement pipes, in unstable waters, pH increases and asbestos fibers can
be found in the water. Surface roughening, strength reduction, and pipe
failure.

Iron
Cast Uniform corrosion Rust tubercles (blockage of pipe)

Ductile Graphitization

Pitting under uprotective scale

Iron and suspended particles release

Steel Pitting Rust tubercles (blockage of pipe)

Iron and suspended particles release

Galvanized Steel General pitting corrosion Excessive zinc, lead, cadmium, iron release, and blockage of pipe

Copper Uniform corrosion

Localized attack
Cold-water pitting (type I)
Hot-water pitting (type II)
Other types of localized attack
Microbial-induced corrosion
Corrosion fatigue

Copper release

Pipe perforation and subsequent leakage from pipes

Leakage from pipes and sporadic blue deposit release. Rupture of pipes
and fittings and consequently leakage.
Leakage from pipes

Lead
Lead pipe
Lead-tin solder

Uniform corrosion Lead release

Lead and cadmium release

Brass Erosion and impingement attack

Dezincification
Stress corrosion

Penetration failures of piping
Blockage of pipes and fittings
Lead and zinc release

Plastic Unknown

Degraded by sunlight and microorganisms?

Taste and odor

Source: Modified from Reference 49.
* No internal lining (e.g., tar).
† Used as internal lining of iron and steel materials.