Sometimes the corrosion is painfully obvious on the exterior of the pipe, as in the photo below.

   But, because the bulk of the corrosion is happening inside the pipe, it may not be obvious until the interior corrosion eats entirely through the pipe. The two photos below show a section of galvanized pipe that was recently replaced. The side view does not indicate any distress but, looking into the open top end is a different story.

   Several insurance companies will not insure an older home (over 40-years) with original galvanized water piping still in place. Others do not require replacement, but will set an extremely high deductible for water damage or want certification of the condition of the pipe by a licensed plumber. The cost of re-plumbing the average home’s water supply piping starts at about $5,000 and, usually, the new piping is run through the attic, then down to the plumbing fixtures, leaving the original galvanized pipe abandoned in place.

    Galvanic corrosion, an electrolytic reaction between galvanized and adjacent copper pipe, can cause early pipe failure of some portions of a home’s galvanized steel piping. It usually occurs at pipe connections near the water heater. To learn more about it, see our blog post ”What’s the powdery crust on the pipe connections at the water heater?”

While we hope you find this series of articles about home inspection helpful, they should not be considered an alternative to an actual home inspection by a local inspector. Also, construction standards vary in different parts of the country and it is possible that important issues related to your area may not be covered here.
© - McGarry and Madsen Inspection


More Blog Posts on Similar Subjects:

  1. Should I upgrade to a tankless water heater?

  2. How old is that water heater?

  3. What is the purpose of a thermostatic mixing valve above a water heater?

  4. Are there water lines in my attic or under the floor slab?

  5. Should I wrap the water heater with an insulation blanket?

  6. How do I get insurance if my home can’t pass a 4-point inspection?

  7. Do you check the plumbing under the floor slab?

  8. How do I get rid of the sewer gas smell in my house?

  9. Do I have polybutylene pipe? Why is it a problem?

  10. What is a P-trap?

  11. What is well pump “short cycling”?

  12. How do I remove cigarette odor in a house?

  13. What’s the flip-up handle on the water heater for?

  14. How come the water has a rotten-egg smell in some empty houses?

  15. My well water test came back positive for bacteria. What should I do?

  16. Do you test the well water?

  17. What is that big thing in the toilet tank?

  18. How much does it cost to replace the water heater?

  19. How can I tell what type of plumbing pipe I have?

  20. What is the difference between a regular water heater and a power vent water heater?

  21. How do you test a shower pan for leaks?

  22. What is a dielectric union?

  23. What is a heat pump water heater?

  24. What is the average life expectancy of copper pipe?

  25. Why can’t PVC pipe be used for water pipe inside a house?

  26. What is the average life expectancy of PVC pipe?

  27. What is an auto vent, air admittance valve, or check vent?

  28. Why is a European-style bottle trap not approved by the plumbing codes in the U.S.?

  29. What are the requirements for installing a gas appliance connector?

  30. What is an escutcheon plate?

  31. Why is sunlight exposure bad for PVC pipe?

  32. What is the loose wire sticking out of the ground under the gas meter for?

  33. How can I locate my septic tank?

  34. What do the ABS, PVC, CPVC, PB, and PEX plumbing pipe names mean?

  35. Should I seal the washing machine drain hose to the standpipe?

  36. How can I tell if a house is connected to a septic tank or sewer?

  37. What is a sediment trap or dirt leg?

  38. Is a hot water faucet required at a washing machine?

  39. Which plumbing fixtures require water shut off valves in a home?

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