Terry: I have not appointed myself as the last word on copper pipe failure,
but I sure have spent a lot of time, energy and money in the effort to shed
some light on the subject. There are several types of corrosion.
It is the Internal type that accounts for the vast majority of pin hole leaks
that I have dealt with over the years. I will discuss the others if you wish
Pin hole leaks and the leaching of copper into the potable water is a
pretty straight forward proposition.
By far the highest incidence of this type of failure is due to
"Electrolytic Corrosion." Most water has the ability to conduct an electrical
charge (this makes it an electrolyte). It isn't poisonous like the
electrolyte found in your cars' battery, but it is an electrolyte
nonetheless. The more dissolved naturally occurring minerals and gasses that
are found in the water, the more effective it becomes as an electrolyte.
In order for this electrolyte (water) to do its' dirty work, it needs
some fuel to drive the corrosion process. The term "Electrolytic" can be
exchanged for electrolysis which is the reduction of water to its basic
building blocks of 2 Hydrogen atoms and 1 Oxygen.
The metallic salts, non metallic salts or gasses present in the water
will quickly form a bond with this freed oxygen and Hydrogen to form simple
and complex compounds. For instance if the water is from a municipal, it will
most likely contain
Chlorine to inhibit critters from living or multiplying in the water, this
Chlorine will have an affinity with the liberated Hydrogen and form
Hydrochloric gas or hydrochlorides (depending on what minerals are
present..Magnesium..Calcium.. etc. This conversion in turn increases the
conductivity and effectiveness of the water.
Hydrochloric gas (or acid) can form the basis of those green (stains
copper chloride) that generally indicate something is amiss with the copper
piping system...Free Sulfur will form blue stains of Copper Sulfate..or worse
into Hydrogen Sulfide gas.
The fuel mentioned above is a minuscule DC voltage that is typically
milivolts, the source of this electrical energy depends on who answers the
With a copper pipe carrying an electrolyte and a teen tiny amount of
electrical energy available, the stage is set for the pin hole leak scenario.
As Hydrogen levels rise so does the pH increasing the conductivity of the
water as well as its' aggressiveness. At this point copper atoms in the walls
of the tubing start to shed ions (and go into solution), the metallic copper
in the water goes up and up until it starts to taste bitter (to those with
discerning palettes). If you live in an older home the heavy metal content
will also go up from the lead solder joints and the tin from brass valves and
This munching of the copper atoms will continue until one of the
corrosion sites will burst through the tubing wall as a slab leak or a more
easily repaired wall or ceiling leak.
I manufacture a NSF certified device that overwhelms the corrosion
process by furnishing bazillions of Magnesium Oxide Ions to the beleaguered
pipe walls and consumes the bulk of the destructive DC current in the
process. It is based on the sacrificial anode concept that has been around
for at least a century or so, the main difference being the use of an "Active
Anode" instead of a passive one.
Didn't mean to run on so long, if your interested I can tell you of other
corrosion problems at a later date.
Yes, I believe any additives (like Chlorine Tablets) can and will hasten
the demise of copper piping.
Copper DWV drainage takes a bad hit from H2 SO gas that can evolve from
sulfur containing compounds or traces in the water. This gas can disintegrate
copper on contact as well as brick manholes, VC pipe and ferrous metal
Suncoast Plumbing Inc.
Link to web site below
: I don't believe this is from the Chlorine tablets, I have seen the same
: situation in Ohio on well systems I am forced to agree that it is from the
: sewer gases.
: In the mid 60's their was a period that copper was not manufactured to the
: highest standards the regulations of copper were lowered something to do
: with the Vietnam war. I am not to sure I am to young this is what my dad
: told me I have also seen some thin copper in pressure copper for the same time. Bob Beall
: I looked at your photo. I assume that it is rotated correctly, the leak was on the bottom. I've seen this many a time with copper. Cause ... The owner of this property did not flush their toilet after each use. Lets assume that the mister goes to bed late and did not flush because the toilet does make some noise. Some time later the Mrs. gets up and she goes, again she does not flush, maybe one child does the same. Pretty soon you have a high concentration of urine. Any more use from any family member and as water finds it's own level you have a corrosive liquid gradually taking out the copper. Usually a family with this habit will also have the build up in the jet hole in the bowl. You can send the sample to the Copper Development Association www.copper.org They will analyze and give you a report.
: Bill Parr
: I have replaced the same line as you and the home owner put a 2
: bricks in his tank to save water. I think the heavy concentration of
: urine and being only DWV had a lot to do with the deteriation of the
: pipe.This pipe was only 3 yrs old. Back in 1965.
: Dale's Plumbing Service Inc LMP
: I looked over the photo, and surely believe that I've seen this before in a couple of cases. The sewer gases theory is correct, but the chlorine tablets, if flushed, could be the causative of contributory agent. The reasoning? So:
: One of the waste products of anaerobic bacterial action on sewage is Hydrogen Sulfide gas. (H2S) As this gas travels up the sewer from the septic tank or other source, it is combined with the water vapor in the air in the pipe. The product compound, H2SO4, is best known to us as Sulfuric Acid. As it is condensed to it's liquid state, it runs to the bottom of the pipe, then down the entire line, corroding at the invert until failure.
: The same scenario can occur with Chlorine gas. Once release as free Chlorine, It can combine with Hydrogen as HCl, and with water to form Hydrochloric Acid, and then the process is the same as above.
: A possible test to determine the culprit in this case would be to have a qualitative analysis performed on the scrapings from the damaged pipe to determine if the corrosion solids are Copper Sulfate, or Copper Chloride/Chlorate.
: Lrak---Still lurking around in orbit on the mothership, waiting for the opportunity for world domination when you puny earthling drop your guard for just one minute. Karl Dennis Conley
: Sort of like cleaning rat urine in a bath remodel with Clorex. That creates that terrible gas you are talking about. I had to leave the room. I found it better to paint over it with Zerolac white lacquer to "mask and seal" the smell.
: We have found that in some piping the drain line is rotten on top and
: other times on the bottom.
: When a sewer gas is not vented properly out the roof the gases stay in
: the pipe and eat away on the top side that all most never gets washed
: clean with fresh water. One.sixes will be causing this on the older
: systems very $oon. Be ready to make more money$.
: One.sixes need smaller sewers and other means of washing the piping.
: Remembering the old wet venting with a drinking fountain at the top most
: area to wash the vent stack.
: We use to put in flushing systems on drink dispenser drains. That shut
: them of to save water. $$$$$$$$$$$ Them we broke up floors to replace
: the piping. Great $aving on water. James Rauer
: I saw copper ate out by sewer gas at the closet bend and at the wall where trap connects. I guess the sewer gas goes up to trap seal and gets strong at that point, That's why here in St. Louis Mo we could not use dwv anymore, it has to be L cop. I also saw copper ate up by chlorine, but it was a stronger kind, not those tablets you put in bowl, copper is to high to use anymore for waste.
: art retired plbg
: original message:
: : Have you ever wondered what happens to copper drain lines when you use chlorine bowl cleaning products? The picture above should scare you. The picture shows a three inch copper DWV pipe removed from a closet bend. Needless to say it was a pretty bad leak. I've seen this on commercial bar sinks also. Replacing copper DWV with plastic pipes is the best solution on them, unless it's a fire rated building in which case cast iron may be needed. On them, it's the combination of limes and lemons I believe. Terry