While the Seattle Gum Wall has its pluses and minuses, it is at least not pretending to be anything other than what it is. Whether the viewer sees it as “art,” “graffiti gone awry,” or just plain “disgusting,” is pretty much left to the viewer.
At a recent inspection I found some gum like substance being used in an attempt to stop leaks at a corroded water faucet. I use the word “attempt” because it was clearly not working.
With old galvanized plumbing like this, there really is no “fixing” a leak–it typically requires replacement of the offending components. Often any attempt to replace components of old galvanized plumbing systems results in corrosion being dislodged inside the pipes that then travels with the flow of water to points where it clogs portions of the pipe that are not rusted through–or gets hung up in fixture valves and/or aerators.
Plumbers stopped installing galvanized water supply systems in homes in the early 50’s typically. Given a 40-50 year life expectancy–depending on water quality–this time line would place nearly all galvanized plumbing systems at the end of their useful life. In the Seattle area, where we have water that is exceptionally friendly to galvanized plumbing, I routinely see piping close to 100 years old and still more or less “functional.” Functional flow will get worse over time and even though there may not be active leaking, the system may be less than fully functional as the inside diameter of the pipe becomes smaller and smaller due to corrosion. 
With the older systems I see, there is almost always lots of “autogenic healing” where the pipes have leaked and then sealed themselves by rusting closed. They open up after a while and start leaking again and then will usually seal themselves again. Eventually they will not self-heal and the leaking becomes continuous. That is what has happened with the gummed up valve in the picture above. It is time to move from chewing gum to replacement.
Certainly anyone buying a home with galvanized plumbing today–should be planning for replacement of the plumbing tomorrow. I don’t mean “tomorrow” literally, but when you can no longer tolerate poor flow at the shower head when someone flushes the toilet, or get tired of waiting for that pot to fill, it may be time to think about replacement.
By Charles Buell, Real Estate Inspections in Seattle
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I didn’t know there was such thing as autogenic healing. It is really interesting that a pipe could rust its’ self back shut. If something like this is happening, replacement is definitely my first thought. Thanks for sharing.