Help! Attack of the pinhole leaks.

zvalve

I have replaced part of the offending pipe with pex but an area I covered with insulation went unnoticed and developed many leaks. Photo attached to show problem. It is at a junction which goes to a vertical run starting with a valve. What do I do?

Larry Weingarten

Hi, I'm wondering about water quality. Has it been tested? I'd just replace that with PEX also.

Yours, Larry

DanHolohan

Where is this house?

mattmia2

DanHolohan said:

Where is this house?

Did anyone ever definitively figure out what your problem was? The stuff I saw sure looked like it was stray current from some sort of utility bonding issue.

Jamie Hall

That type of pinhole leaking in copper is usually water with a low pH. It would be worth checking and correcting. But replace all the copper you can find and get at with peX.

zvalve

Thanks for your replies but the reason why this occurs remains a mystery. House is in Long Island, NY. No one has figured out what is going on. The house is grounded on the water supply line before the water meter. I am not sure if there is also a grounding rod as well. Much to my surprise, after internet research, which isn’t all that rigorous at times, it seems as if this problem has not been solved and there is not a consistent answer backed by scientific explanation. Possible theories include:
1.low ph of water supply
2. Use of corrosive flux
3. cheap or thin walled copper pipe
4. improper installation of pipe with no debarring which causes turbulence.
5. High pressure and flow rate
6 Turbulence but why it causes corrosion never explained.
7. Galvanic corrosion but how a mystery 
No theories have been supported by repeated experiments or found in peer review journals. This is an insidious phenomena and illustrates one backward state where human knowledge still resides. 

jesmed1

I would suspect #3. Some people have said that a few decades ago the market was flooded with cheap imported pipe with impurities that soon developed pinholes. I remember once I bought a cheap imported stainless steel cook pot, and soon after using it, a rust pit developed. I'd never seen stainless steel rust, and evidently there was some impurity in the "stainless" that was, in fact, rusting.

I'm also reminded of the toxic Chinese drywall that flooded the market a while back. It offgassed sulfur, which, in an odd coincidence for this thread, attacked exposed copper (in home wiring and pipes) and turned it black.

Gsmith

Could very easily be a bad ground or unbonded neutral at your house, even at a neighbors house or a utility problem, might want to check with a good electrician, and/or call the electric uitility and have them check their side.

ChrisJ

jesmed1 said:

I would suspect #3. Some people have said that a few decades ago the market was flooded with cheap imported pipe with impurities that soon developed pinholes. I remember once I bought a cheap imported stainless steel cook pot, and soon after using it, a rust pit developed. I'd never seen stainless steel rust, and evidently there was some impurity in the "stainless" that was, in fact, rusting.

I'm also reminded of the toxic Chinese drywall that flooded the market a while back. It offgassed sulfur, which, in an odd coincidence for this thread, attacked exposed copper (in home wiring and pipes) and turned it black.

There's many grades of stainless steel, and multiple things that can cause them to rust for different reasons. It doesn't mean it has impurities or that it's not stainless. And then of course, there's products that aren't what they claim.

I agree with @Jamie Hall , low pH.

Jamie Hall

Jamie Hall said:

That type of pinhole leaking in copper is usually water with a low pH. It would be worth checking and correcting. But replace all the copper you can find and get at with peX.

I only speak from my rather extensive -- and expensive experience. On a number of properties, over the last six decades or so. I've seen this often enough, and I've almost always found low pH. I regret that I haven't done an internet search, however,, nor am I peer reviewed, nor have I done any extensive research. Sorry.

hot_rod

Outside in corrosion? Something trapped under the insulation?

Is it only in one location?

MaxMercy

The green is the copper "rusting" back to ore, so I'd rule out crappy pipes.

If all the leaks are confined to one specific run, I'd be looking at galvanic corrosion. If they're random (that's what I had) leaks I'd be looking at water quality. In my case, my pH was about 6.4. Once I added an acid neutralizing tank the problems stopped.

Do you have evidence of green/blue deposits at your fixtures?

zvalve

Yes it is in one location, from the water heater horizontally to a branch off point to upstairs apartment. Before this run there is another horizontal branch and run to hot water valve in front of garage for car washing. No corrosion on that run, it rarely gets used and is shut off by ball valve about 6 ‘ from water heater This infers that use of hot water in house upstairs and down is some how contributing to problem, since hot water is frequently flowing through the offending pipe. This pipe is lowest run house. 

EBEBRATT-Ed

Hot or cold water??

Looks like cold to me.

If it's cold water it could be flux.

Hot water washes flux away

Larry Weingarten

Hi, That pipe has to come out one way or another. When you take it out, save a piece and cut it lengthwise. This will give clues about what happened. NACE, the National Association of Corrosion Engineers might have information that will help explain what happened.

Yours, Larry

hot_rod

The CDA Copper Development Association also has all sorts of data for troubleshooting copper problems.

MikeL_2

   I would be cautious of replacing all  exposed, accessible copper piping with pex where it has been subject to low ph water, unless the water is neutralized.
      Often, the affected, corroded copper is sacrificial and as the water attacks the exposed copper, it loses some potency and prevents damage downstream.
   Untreated low ph water will travel through new pex and attack hidden copper, faucets, valves, etc. where access for repairs can be a challenge.
   

mattmia2

if the water is that aggressive toward copper and it is municipal water, wouldn't it be failing the copper rule testing assuming they are doing it at least somewhat correctly?

zvalve

Thanks posters, awesome, great heating help, especially hot_rod and Larry. I have to admit I was wrong about research on pitting because hot_rod suggested I consult the Copper Development Association which has a great pdf explaining 7 causes of pitting and possible mitigations, https://copper.org/publications/pub_list/pdf/a4073.pdf. Problem could be much more complicated than I thought. Larry I will also consult National Association of Corrosion Engineers and see what they have to say and report back. 

ChrisJ

If that was my house I'd start converting it all over to pex.

My reasoning is such.
I highly doubt the piping in the walls is much better if at all better than the exposed piping, so it's not far behind failing. Even if it's type L and the stuff you removed is type M, it's not going to be that big of a difference in this regard.

If low pH is the reason, pex will solve it for the most part.
If stray current is the problem, pex will also solve it.

Practically every cause for this will be solved by pex.


Fix the problem while you can plan it around your schedule. Don't wait for it to fail and cause serious damage when you're not home etc.

Rizz861

I would start by checking all of your hangers. I’m sure water quality, cheap copper, and electrical grounding/bonding do play a role, but I feel the culprit is usually an incorrect hanger (galvy) touching the copper causing it. At least that is my experience. I’d rule that out before you start going crazy with everything else. 

Allislandradiant

What does the inside of the pipe look like? 

Intplm.

@zvalve Water quality and electrolysis. Integral with each other. The two most common things that usually cause the problems you have pictured.

farmwi

Another cause of pinhole leaks not in pdf, maybe not this one, but where to check. I see sharkbites..

Used to work in water. Ended up being responsible for replacing water line near the exit of a building. After vacuum digging for a week in flowing sand, became motivated to consider why here, it led to more discovery.
Thanks to electrical code wanting a ground, occasionally, there is some stray current via many possible methods applied to a ground, which is also applied to the pipes. Current takes all paths.

The ground rod is required to have less than 50 ohms resistance, but that doesn't mean current won't travel out of the copper supply pipe into the ground around it, causing pin holes just outside of the foundation.

There is also the pushfit / sharkbite problem which creates an electrical separation, where two pipes are nearly butted together and electricity flows through the water from one to the next, pitting the inside.

There is also the bad neutral (not quite 0 ohms) connection down the street, so current flows from N to ground to water pipe to main water pipe to next house ground to to neutral then back to transformer.

There is also, the house on one transformer, connected to the water system on another transformer. Any difference in Neutral may cause current to flow.

Poor Neutral connection to transformer will cause current on the ground rod to seek the xfmr ground rod.

Least likely, power closely paralleling a pipe over a distance can induce current.

Anytime I see tells of green oxidation I get out the good sensitive meter with a best current clamp.
Place clamp right over suspect tube/wire.
Just bc you don't see potentials now doesn't mean it might not be part time with a switched circuit.
Check for current on ground wire at the electrical service entry panel. Should be none.
Check for voltage between Neutral and ground. Should be none.
Check for voltage difference on both sides of push fit. (even brass push fits sealed by O-ring and plastic retained ss teeth may completely electrically isolate each side of a connection)
Check for current on water line entry before ground connection.
Check for current on water line to remote building bad Neutral will cause current return on pipe.

If you connect a 15amp breaker, a 120v line-Neutral to a 40 ohm ground(s), the breaker will not likely open.
120/40 ohms = 3 amps. You have a 360 watt power distribution somewhere.

ChrisJ

farmwi said:

Another cause of pinhole leaks not in pdf, maybe not this one, but where to check. I see sharkbites..

Used to work in water. Ended up being responsible for replacing water line near the exit of a building. After vacuum digging for a week in flowing sand, became motivated to consider why here, it led to more discovery.
Thanks to electrical code wanting a ground, occasionally, there is some stray current via many possible methods applied to a ground, which is also applied to the pipes. Current takes all paths.

The ground rod is required to have less than 50 ohms resistance, but that doesn't mean current won't travel out of the copper supply pipe into the ground around it, causing pin holes just outside of the foundation.

There is also the pushfit / sharkbite problem which creates an electrical separation, where two pipes are nearly butted together and electricity flows through the water from one to the next, pitting the inside.

There is also the bad neutral (not quite 0 ohms) connection down the street, so current flows from N to ground to water pipe to main water pipe to next house ground to to neutral then back to transformer.

There is also, the house on one transformer, connected to the water system on another transformer. Any difference in Neutral may cause current to flow.

Poor Neutral connection to transformer will cause current on the ground rod to seek the xfmr ground rod.

Least likely, power closely paralleling a pipe over a distance can induce current.

Anytime I see tells of green oxidation I get out the good sensitive meter with a best current clamp.
Place clamp right over suspect tube/wire.
Just bc you don't see potentials now doesn't mean it might not be part time with a switched circuit.
Check for current on ground wire at the electrical service entry panel. Should be none.
Check for voltage between Neutral and ground. Should be none.
Check for voltage difference on both sides of push fit. (even brass push fits sealed by O-ring and plastic retained ss teeth may completely electrically isolate each side of a connection)
Check for current on water line entry before ground connection.
Check for current on water line to remote building bad Neutral will cause current return on pipe.

If you connect a 15amp breaker, a 120v line-Neutral to a 40 ohm ground(s), the breaker will not likely open.
120/40 ohms = 3 amps. You have a 360 watt power distribution somewhere.

I'm sorry, I do not understand this statement. Can you be more specific?
Because, the neutral and ground are required to be bonded together.

bmcservice

Dealing with this on Long Island for too many years. Check into all of the suggestion's electrolysis, water velocity, circulator friction, etc. The most common factor is chlorine. The water companies will bump up chlorine levels to acceptable for drinking BUT not copper pipe.

EBEBRATT-Ed

Long post. And the OP cannot tell us if it was a hot or cold-water pipe.

Sal Santamaura

bmcservice said:

Dealing with this on Long Island for too many years. Check into all of the suggestion's electrolysis, water velocity, circulator friction, etc. The most common factor is chlorine. The water companies will bump up chlorine levels to acceptable for drinking BUT not copper pipe.

Actually, the problem is when chlorine gets replaced by chloramine. When we had pinholes breaking out throughout the house (here in southern California, not Long Island), I bit the bullet and had our entire house re-piped in Uponor pex. By the way, the water's pH here has always been alkaline.

ChrisJ

Curious what is used for chlorine in public water? I.E. are they using sodium hypochlorite?

"Chlorine" isn't a chemical to my knowledge?

JustinTheCarpenter

zvalve said:

Yes it is in one location, from the water heater horizontally to a branch off point to upstairs apartment. Before this run there is another horizontal branch and run to hot water valve in front of garage for car washing. No corrosion on that run, it rarely gets used and is shut off by ball valve about 6 ‘ from water heater This infers that use of hot water in house upstairs and down is some how contributing to problem, since hot water is frequently flowing through the offending pipe. This pipe is lowest run house. 

I've dealt with this in a few places in Bucks County PA. Acidic water & red label copper was the most frequent cause. If it's just that section replace it & keep an eye on the rest. Check any other copper you can get easy access to behind access panels too.

Jamie Hall

ChrisJ said:

Curious what is used for chlorine in public water? I.E. are they using sodium hypochlorite?

"Chlorine" isn't a chemical to my knowledge?

De[ends on the treatment process and flow volumes. I very large plants it will usually be chlorine gas directly injected, which dissolves readily and is easily controlled. In smaller plants sodium hypochorite can be and is used, but the stuff is a fire hazard and has to be handled carefully. The result is elemental chlorine dissolved in water. Many plants also add small amounts of ammonia at the same time to create chloramines (quite deliberately) and chloramines do almost the same job of disinfecting, but don't react readily with other organic compounds which may be in the water and thus give a more stable residual. The aim is to have between 1 and 2 mg/l chlorine or chloramine in the water throughout the distribution system at all times. Long dead end distribution pipes are a particular headache... the frequency with which testing is done varies with the size of the system.

And may I point out. You may not like the smell or flavour -- though most people are accustomed to it -- but it is there for your health.

hot_rod

Chloramines are also used, ammonia added to the chlorine.

Geosman

I've seen similar in homes with super soft water. If its happening on a DHW line it's likely the anode in the hot water tank is depleted or missing or they are using a stainless steel boiler or indirect tank for domestic water in which case there is no sacrificial anode. I've used a high temperature polysulfone water strainer filled with cut up magnesium anode rods to help protect the copper in several homes with this issue. The rods need to be replaced about every 9 months and so far no more leaky pipes. This was alot easier than tearing out walls to access and replace copper lines.
https://www.supplyhouse.com/Rusco-1-1-4-100-HT-F-1-1-4-Hot-Water-Spin-Down-Filter-System-100-Mesh?_br_psugg_q=rusco+spin+down

DanHolohan

https://heatinghelp.com/systems-help-center/a-copper-mystery/

scott w.

I would have to agree with Dan Holohan and gs Smith. I think you should investigate the stray current. Have seen this before. Need to find a really educated electrician that knows grounding and has proper equipment (ability to read milliamp voltage) to find stray current. Very very tiny current flow of milliamps can be the cause of the galvanic deterioration. Any electrical wiring with a metal sheath touching the copper piping? As someone mentioned above post, even a neighbor off the same electrical transformer out on the utility pole can cause issues. Look at the utility pole where the transformer is mounted and make sure the ground wired coming down the pole is connected to a rod.

Any other energized wiring come in contact with the copper piping? Proper grounding techniques are important. Are the electric and telephone tied to the same ground rod? I knew of one electrical firm in Ohio that did excellent work in finding and then fixing stray current that would cause major problems in telephone switch rooms. The firm would do an audit of the whole building and write up all the issues found. I can verify that once the firm fixed issues found in the grounding audit, maintenance and repair costs dropped dramatically. One question to ask the home owner if they see and unusual amount of appliance repair or computer stuff that that goes bad. Stray current will weaken computer chips in those devices and will fail prematurely.

ChrisJ

Can someone please explain to me how current traveling through an all copper pipe far away from any dissimilar metals causes galvanic corrosion please?

I do not understand.

hot_rod

Maybe these people can, Chris?

https://www.corrosionclinic.com/types_of_corrosion/stray current corrosion.htm

ChrisJ

hot_rod said:

Maybe these people can, Chris?

https://www.corrosionclinic.com/types_of_corrosion/stray current corrosion.htm

Hi Bob,

According to that page,

How to identify stray current corrosion? Stray current is a dynamic and transient phenomenon. Corrosion ONLY occurs at the point of discharge (POD). At the point of entry (POE) and along the entire system that carries the stray current, there is NO corrosion. In fact, at the point of entry, stray current provides certain degrees of cathodic protection to the metallic structure.

hot_rod

I looked up a couple opinions on stray current, even the CDA claims it is not well understood. And they are the copper tube experts.
As a result there tends to be a lot of different theories and opinions on how and why stray current attacks copper tube.

And it seems DC current has even different characteristics?

I recall one job, actually city hall in Park City where pin holes developed where the BX cable sagged touched the copper waterlines. A black mark with a pin hole. They showed up rather quickly after the building was remodeled within a year or so. So was it from dis-similar metals, although it was dry, no moisture as an electrolyte, or was it due to the current, from the grounded jacket?

ChrisJ

hot_rod said:

I looked up a couple opinions on stray current, even the CDA claims it is not well understood. And they are the copper tube experts.
As a result there tends to be a lot of different theories and opinions on how and why stray current attacks copper tube.

And it seems DC current has even different characteristics?

I recall one job, actually city hall in Park City where pin holes developed where the BX cable sagged touched the copper waterlines. A black mark with a pin hole. They showed up rather quickly after the building was remodeled within a year or so. So was it from dis-similar metals, although it was dry, no moisture as an electrolyte, or was it due to the current, from the grounded jacket?

Don't know.

That previous article claims corrosion only occurs where it discharges, so if that's true it suggests the pipe was hot and discharging to the grounded jacket. Or as you said, just dissimilar metals. Perhaps the pipe was sweating in the summer?


For right now, I'm not buying the stray current claims on a pipe that's corroded randomly out in space with nothing touching it. Where a grounded MC / BX cable is touching it makes sense, but not in the OP's case.

I don't see copper wire, or even aluminum wire corroding randomly just because there's current flowing through it.

hot_rod

ChrisJ said:

hot_rod said:

I looked up a couple opinions on stray current, even the CDA claims it is not well understood. And they are the copper tube experts.
As a result there tends to be a lot of different theories and opinions on how and why stray current attacks copper tube.

And it seems DC current has even different characteristics?

I recall one job, actually city hall in Park City where pin holes developed where the BX cable sagged touched the copper waterlines. A black mark with a pin hole. They showed up rather quickly after the building was remodeled within a year or so. So was it from dis-similar metals, although it was dry, no moisture as an electrolyte, or was it due to the current, from the grounded jacket?

Don't know.

That previous article claims corrosion only occurs where it discharges, so if that's true it suggests the pipe was hot and discharging to the grounded jacket. Or as you said, just dissimilar metals. Perhaps the pipe was sweating in the summer?


For right now, I'm not buying the stray current claims on a pipe that's corroded randomly out in space with nothing touching it. Where a grounded MC / BX cable is touching it makes sense, but not in the OP's case.

I don't see copper wire, or even aluminum wire corroding randomly just because there's current flowing through it.

I guess it comes down to which "exert" you want to agree with?

I think stray current gets blamed when no other obvious condition exists, aggressive low ph, excessive velocity, solder flux, un-reamed tube, hot ground, etc.