I have a lot of 0.5" galvanized pipe in my house. Most of it is around 110 years old; what little I have disassembled has been in pristine condition.

However, there are some spots near the (poorly installed) water heater which are beginning to pin hole. I suspect this was due to running heated salinized water through iron, or some kind of electrical issue, since nowhere else in the house do I see any trace of damage.

However, I want to determine to the best possible extent whether or not this is the case, particularly as I have several supply lines exposed at the moment; if I don't replace them now, it will be difficult and expensive to do so later. However, if they haven't worn significantly in 100 years, then they'll probably last at least another 100 or more.

From the outside, they appear to be in pristine condition, except where an old (fixed) leak in the roof caused the exterior of a couple areas to rust slightly (surface rust, no pitting or pinholing).

So: what can I do (aside from pulling them apart, and thus risking damaging the seals and pipes) to determine their condition?



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Put a pressure gauge on an outside spigot and remove the aerators from all your faucets, then turn on all the fixtures and flush the toilets. you can gauge whether the inside diameter is reduced from corrosion by how sharply the pressure drops under a load. I was in a house that was so restricted that the owner had removed the pressure reducer and the hot water tank started spraying. When I put a gauge on it, the static pressure was over 175 psi, but if you turned on the bathtub, it dropped to under 5 psi and water wouldn't work anywhere else in the house, and the tub was only a pencil sized stream. I suspect that there was less than a 1/8th inch diameter in the main water line somewhere before the water heater, but after the PRV.

I'll have to retest (I had an inspector do that test when I got the house, but I think he bungled it); however, in the meantime, the simple fact that I can run a sink and flush a toilet while running a bath without detecting any change in bath water temperature probably means there isn't any significant drop-off.

The only way to tell someone else is running water is by listening for the faucet, since the plumbing is completely silent

I question whether any house would have 1 1/2" water piping in it.

the trouble spots on galvanized piping is where ever there is brass and galvanized joined together. in the old days they would just run a pipe, screw on a brass shut off and continue with iron pipe. sometimes in order to have a chrome pipe under a sink or toilet they would transition to copper and then to brass.
anyway, all the places where the two disimilar metals meet can be a trouble spot.

Indicating the age of over 100 years and if I understand your question, I seriously would consider replacing all of it while it is open and before you button it up. It allow one to sleep at night. Just an opinion. Good luck with your decision.

We STILL screw a brass valve to a galvanized pipe and then continue with galvanized, at least when we still use galvanized piping.

0.5", not 1.5".