Galvanized steel pipe has been widely installed for domestic cold water service and has generally provided excellent service for over 100 years.  Our ultrasonic investigation relating to galvanized steel pipe installed in 1896 at one downtown New York City building remains our oldest example.  Since then many changes have occurred mostly related to its deteriorating quality and higher corrosion resistance.  Whereas earlier examples of galvanized steel pipe had a layer of zinc protection so thick it could be carved with a knife, the zinc coating for today’s products are so thin they will often not even survive the groove rolling process.

This has produced an interesting dichotomy.  The higher quality older pipe provides far longer life but has been in service a much longer period of time.  New galvanized steel pipe should be at the beginning of a long service interval, yet offers far less service due to its lower quality.  The net result has been to document failures to newer and older galvanized steel piping systems at a similar rate.

Most buildings having galvanized steel pipe are experiencing problems, whether due to leaks, taste and odor complaints, or pressure and flow problems caused by constricting rust deposits.  Today, the replacement of old galvanized steel pipe which originally provided 75 years of service with new galvanized steel pipe offers questionable benefit; that new pipe likely providing 20 or less years of service.

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