Copper Piping and Pin Hole Leaks

Can you hear the turbulence inside your copper plumbing pipes? If you can, it's probably too late. According to an article I read at one of my favorite defective products web sites (recalls.gov), and oooooh how I love those defective products, the most common failure of copper pipes is the occurrence of a pinhole leak due to inner wall deterioration of the pipe.

These common types of failures are caused by water turbulence, scaling or solder-flux runs. As water moves (commonly 6-8 gpm) through a pipe and it hits excess solder or scale it causes turbulence which wears particularly harder on a specific place on the pipe's interior surface until it forces it's way into your living room on Sunday 2:00am sharp. Unfortunately we can't see the interior of our pipes but we can see dents and bends in piping that were not properly created with a bending tool which can also create this same turbulence condition. If you have bent or kinked copper piping, consider replacing it now.

There are also exterior influences on copper pipes that lead to pinhole leaks. Outer pipe deterioration is generally caused by it's contact with alkaloids in cement, galvanic action, dissimilar metals, and corrosive type soils. When you see copper pipe penetrations through concrete block or stucco which I see as a common practice in older homes in our area, think about the copper deterioration. Plastic sleeves are the most common type of protection that will inhibit this caustic relationship and subsequent material deterioration. It also helps prevent mechanical deterioration due to expansion/contraction from normal thermal changes.

Dissimilar metals commonly seen at water heaters or where copper piping is hung with metal strapping/wires and even where house grounds connect to copper piping can all cause galvanic action or electrolysis. That's why there are dielectric unions. The scientific explanation of anode and cathode stuff was just a little too much for this little bit of information. We just need to recognize the potentials to make informed purchase or rehab decisions.

Dissimilar metals, corrosion

Water chemistry has also often been blamed for interior wall pitting/deterioration and you can read studies that prove as well as seriously question that validity. Bottom line…if you ever find very small turquoise spots, this could be the beginning of a pinhole leak, “a breakthrough event” you might say! Please don't pick at these little nodules, you might regret it. Despite how small the exterior evidence is, the interior evidence could be much worse. If you like livin' on the edge and wanna risk it you might get the SBD, the silent but damaging spray that leads to a slew of other problems like wet/damaged flooring and walls which has the obvious adverse mold ramifications if not taken care of right away.

Swiss cheese

I have seen/heard of other studies that contributed pin hole leaks to or in part by low ph, high ph, water softeners, lightning activity, chemical presence, size of pipe, rate of flow, bla bla bla bla. I did see a report by the Washington Suburban Sanitary Commission that did find the overwhelming majority of pin hole leaks occurred in horizontal piping runs, hmmmm. And the smaller the diameter, the higher frequency…Got ½” piping? Cold piping leaks dwarfed hot piping leak frequency, hmmmm. And pre-1960 housing stock bore the brunt in the time line failure looksy. Check it out for yourself, www.wssc.dst.md.us/copperpipe/pinhole_charts.cfm

5,4,3,2,1

The most common residential copper used that has the wonderful reputation for pinhole leaks is schedule M copper. This is the thin walled stuff. Schedule K and L is thicker. K is thicker than L and L is thicker than M. That helps a lot doesn't it. Where ever you can find copper piping exposed, usually at the water heater, look for red letters or striping, that's schedule M. Schedule K and L has blue or yellow lettering/markings. See the attached chart taken in part from the Copper Tube Handbook 2003 as provided by www.copper.org.

Schedule M copper

Schedule L copper

Schedule K copper

So….the most common question I receive is “Will my house experience leaks? Do I need to re-plumb now?” Since God is using my crystal ball right now, I would recommend you base your decision on 1. The visual condition of accessible parts now. 2. The age of the system, everything has an expected/economical life. And 3. The area's/system's historical performance. How do find the area's/system's historical performance? Ask and look. Ask the neighbors, heck you might make a new friend! There is usually someone out walking their dog, picking up the paper, taking the garbage in/out.

If there is an HOA, see if any of the officers are aware of problems. Tell them you are thinking about buying a house in the neighborhood and were a little concerned about the plumbing based on your professional home inspection report (blame it on the home inspector) and wondered if they knew of any problems or of anyone in the subdivision that had their house re-plumbed for any reason. If you receive negative feedback, I would be very wary. However….now you have room to negotiate! Also look for signs of previous repair like drywall patches behind the toilet/s, new stucco/siding at the main water shut off, hose clamps with rubber patches, etc… The more of these you see, the greater the probability your system has a limited life. A quick word on rubber and clamp repair kits…very effective but are temporary NOT permanent. These indications are obviously not a guarantee you will or will not have leaks but as soon as God gives me back my crystal ball, I will ask Him! Your best protection right now (besides a full re-plumb) is called a home warranty and/or insurance!

Temporary repair

So what does all this stuff mean to me? I'm so confused! Studies and evidence can point to multiple causes of pinhole leaks and the frequency of leaks. Good thing is, re-plumbs are really not that expensive when you compare potential personal damage, home damage, health ramifications, etc. If you plan to be away from the house like on vacation, it's not a bad idea to turn the water main off. There is often a pipe that emerges from the ground with an in-line shut off valve and enters the house for ease of use. The water meter is usually a straight run towards the street or rear of the yard to minimize material and labor. If you do not have a house shut off, you can purchase a “plumbing key” at your local hardware/box store for less than $10 that will shut the water off at the meter.