Have had a pinhole leak this year, and also a few years back, so started
looking at my Copper house water plumbing a bit.
Noticed several areas with that bluish-green coating on it.
a. Is this indicative of a pinhole leak developing ?
b. what actually is this bluish-green "stuff" ?
c. Is it a reaction of the Copper with the outside air, and thus
developing on the pipe's outside, or it coming from the inside ?
d. Interesting in that I see it in the middle of a run, here and there,
so it's unlikely that it is caused by any soldering flux residual.
I do also see it at joints, and am wondering if it is caused, here, by a
soldering flux residual ?
Any thoughts on the bluish-green stuff, and pinhole leaks would be most
BTW: how common are pinhole leaks in older (around 35 yr old) homes ?
Copper pinholes show up most commonly in houses with well water,
sometime exacerbated by electrolysis from copper-iron junctions. In
worst cases it is like a cancer and just continues for years until
failures are intolerable. Assess your situation with this in mind. If
you want to eliminate the problem, eliminate the copper. CPVC, and PEX
are well regarded replacements, code approved nearly everywhere, and
have many advantages with the exception of electrical grounding. A
competent journeyman plumber with knowledge of isolation of
electrolytic sources might be able to correct such problems and save
replacing the major parts of your system.
The "stuff" is generally a product of corrosion of the copper from
condensation on the pipe. If you have pinhole leaks developing, plan to
replace all of the plumbing soon. I had a house with rather hard well
water which after 40 or 50 years developed pinhole leaks since it was
corroded from the inside out. After a few leak repairs I just picked up
the necessary supplies and on one weekend ripped out all the old
plumbing and replumbed. That was about 20 years ago and it's had no
There are three different standards of copper pipe classified by the
thickness of the copper. Type M is the thinnest with type L thicker
and type K the thickest. The type of the pipe is printed on the pipe.
You may still be able to read what type it is if you look closely.
Please try to read what type your pipes are and let us know and when
you replace your pipes make sure that it is type K this time. In some
cities type K is mandatory.
If you have had one pinhole leak recently you are probably destined to
have several more soon...
Can you describe where the pinhole leak occurred? Was it near a
fitting which turned a corner, that sort of leak often occurs because
of the velocity of the water at the corner eating away at the pipe
which is helped by very bad water chemistry or a plumber who used
way too much flux when installing the pipes...
a. It can be, or it can be indicative of a lot of humidity in the
where the exposed pipes live...
b. It depends on the chemistry involved, it could be patina, which
naturally occurs on un-coated copper like roofs and gutters, etc...
Or it could be specific chemicals namely: Copper(II) Chloride or
Copper(II) Carbonate depending on your local water chemistry...
c. It could be either or, if your pipes are leaking the process of
corrosion is a mechanical and chemical breakdown and that can
spread out on the exterior surface of the pipe after a pinhole
leak breaks through... Your pipes could have also formed this
color on the outside of them from sweating and having the water
condensation which formed on them chemically react with the
d. Define "middle of the run" are you saying that it is nowhere
near a soldered fitting or joint? Remember the pipes are empty
when originally soldered, excessive amounts of flux would be
washed away and settle elsewhere in the piping upon filling the
system with water...
Sounds like your water chemistry needs to be analyized...
Not knowing whether you are on city provided water or a well
makes a difference... More chloride chemical compounds in
city water usually, more hard carbonate type compounds in
well water... You could also have an issue with sulfides/sulfates
which are reacting with your pipes...
Without knowing what thickness of copper pipe your house has
or your local water chemistry and the volume of water you are
using its not easy to nail down whether 35 years of use is good
or bad performance...
A lightning strike can make a pinhole in a copper pipe. I saw it
happen twice. It usually occurs in the end of a long straight run and
blows out the on or near an elbow. The lightning dont want to follow
the turn in the pipe, so it just blows out the end at the turn.
Generally there's wiring and appliances damaged too.
Thanks for such good info.; really appreciate it.
Some clarifications that were requested:
Yes, it is Type M, apparently. The thin stuff.
Both pinholes developed in a horiz run, nowhere near a joint or elbow.
n 2/25/2011 1:27 PM, Bob wrote:
On Friday, February 25, 2011 11:27:08 AM UTC-7, Bob wrote:
I have started plumbing in small town with a pinhole problem when i go to r
eplace 5 year old copper pipe with pex the pipe is so thin that i can not e
ven cut it with copper cutters, pinholes are a problem, I have stopped usin
g copper altogether Pex is so ugly if the municipality is supplying water t
hat destroys pipes cant they be held responsible,( I have worked in towns w
ith 35 year old copper and older the pipes are almost as good as the day th
ey were put in. the lead solder they used back then oxidizes and causes lea
ks at joints. Aquarise (cpvc)seems like a good copper replacer
My best friends galvanized last near 70 years, he replaced it all with copper which is now failing after 35 years.....
looks like all his lines will need replaced again and he is over 80 and going to get quotes from plumbers......
he is not happy at all......
There's a lot of myth about copper being better then galvanized.
It mostly depends on water chemistry
In my area galvanized can go many years. Soft water.
I replaced most of the galvanized in my last house with new
galvanized. That was +60 years old.
No leaks, but the scale had built up too much, so the water flow to
upper floors had slowed too much.
When I wrenched the pipes open, I found the restrictions were confined
to horizontal runs, only at joints, and much worse around the water
heater. Since the horizontals were mineraled up near the joints, I
replaced everything in the basement from the service entry up to the
verticals that went to the upper floors.
Left all the stuff in the walls alone. They were wide open and not
rusty. I could see that from where they began in the basement, and in
the upper floor els and tees. Replaced all the stop valves up there.
This current house uses the same Lake Michigan water, and the
galvanized is 54 years old, with no issues at all. I know from simple
experience that the joints, especially near the water heater, are
getting mineraled up, but don't know how much.
We don't any issues with flow. Of course that sneaks up on you, since
it happens over time. But you know when it's unacceptable.
This is ranch house, the other was a 2-flat, so it got more water
flowing through the basement pipes. More water, more water heater
activity, more mineral build up.
Of course that's soft water, and apparently high quality galvanized.
Quality pipe is important, whether galvanized or copper.
I don't doubt that some water will quickly clog galvanized, and that
low quality or poorly installed galvanized will leak or rust.
Haven't run into that here.
I've also read that some water doesn't play nice with copper and will
cause pin-holing. Don't know much about copper.
If I get any issues in my current place, I'll just replace it with
galvanized, but might look to see if PEX meets code.
I sure don't see copper as the creme de la creme of piping.
The way I look at copper in my area, it was pushed by builders,
plumbers, and maybe some real estate agents. It adds no value, just
Not sure about the real estate agents, because I've done a lot of
house hunting here, seeing both copper and galvanized, and don't
recall an agent ever even mentioning it.
Most houses here built since the '60's have copper.
Since I don't do copper, I would always look at that as a demerit if I
even gave it any thought. But I don't remember even thinking about
it. Too many other elements of a house are more important.
Copper is totally unnecessary for areas supplied with Lake Michigan
I see pin-holing happens with copper pipe, and nobody knows why.
The original question was asked almost 3 years ago, so it looks like
they still haven't figured it out.
This place is all galvanized
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