Inspect Pipes for Corrosion-Leaks
How to detect points of leakage in supply & drain pipes

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Spot leak points in copper piipes caused by aggressive, corrosive, low pH water - acidic water:

This article describes inspection points to find leaks or corrosion and pitting in copper water supply or copper drain piping in buildings.

This article series describes effects of low pH, acidic or corrosive water on building piping, leaks, dissolved copper, health hazards, and the plumbing system in general.

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Inspect copper piping for leaks, corrosion, pinholes & leak risk factors

Type M copper piping labeling (C) Daniel Friedman

As we note at CORROSIVITY or ACIDITY of WATER, corrosive water is responsible for health effects of increased lead, copper or other contaminants in drinking water and corrosive water in building plumbing & heating systems is also responsible for costly leak damage.

Here are some inspection points that help find corrosion-induced leaks in copper supply and drain pipes in buildings.

  1. Identify the copper pipe type: First, what quality of copper has been installed? Copper piping is sold in different weights or thicknesses.

    M is thin-walled, used in heating baseboards (you should be ok with that as the water in a hot water heating system does not keep changing out so corrosivity is normally limited);

    Types K (thickest) and L copper are used for water piping, M being the heavier grade, more resistant to corrosion perforation.
  2. Inspect both water supply pipes and copper waste pipes too. Pinhole leaks in copper pipes can occur on both supply and drain piping.

    Corrosive water combined with waste and waste water increases the risk of corroding copper drain piping. Pinholes can form anywhere on copper water supply piping.

    Drain pipe leaks in copper pipes, if caused by corrosion, form differently. Surprisingly you need to look along low-sloping runs of copper drain piping for evidence of corrosion or leaks along the top of the copper drain pipe, not just the bottom.

    That's because droplets of highly corrosive condensate form along the upper surface of the pipes and remain in place for long periods, never being washed away by drain usage.

  3. Test the corrosivity of the water supply. Beginning at CORROSIVITY or ACIDITY of WATER we explain that corrosive water increases the chance of leaks in copper piping.
  4. Look for blue dots or pinholes along the copper pipe surfaces: For all copper pipes, but particularly if your distribution piping is Type L, you should inspect for corrosion on the pipe exterior - and beware that a small blue dot, when you scratch it, may become a rapid leak.

    Because the piping is corroding from the interior out, you won't see how thin and fragile other piping sections are ... until the next leak.

    Watch out: Don't ever "pick" at corrosion on water pipes, water tanks, heating boilers, water heaters, calorifiers, cylinders: unless you're prepared to shut down the water supply and clean up a leak.

Copper pipe corrosion and leak risk (C) Daniel Friedman

  1. Look for larger areas of corroded piping such as that shown in our photograph at the top of this page and in our photograph just above. More likely the thick green copper-oxide on the copper pipe in the page top photo is from a larger leak on the other side of the subfloor through which the pipe is passing.

    In the photo just above leaks at a bathroom toilet have stained the subfloor and both supply and drain pipes in this New Jersey surgical center. These are external corrosion and leak signs rather than signs of leaks caused by internal corrosion of the pipes.

Condensation on copper water pipe (C) Daniel Friedman

  1. Look for signs of active leaks: water stains on building materials below the piping or in severe cases, wet lengths of piping or wet building surfaces near or below the pipes.

    Watch out
    : don't confuse condensation on water pipes with leaks. Our photo shows condensation on cold water supply pipes in a damp crawl space.
  2. Replace leaky copper piping: The bad news that has come up with some InspectAPedia readers, is that if you discover a length of copper piping with imminent or current pinholes, replacing just that section is not very comforting.

Other Causes of Pinhole Leaks in Copper Pipes in Buildings

Copper pipe ground bonding (C) Daniel Friedman

Other causes of copper pipe pinholing or holing and leaks include

We joined in investigating a site that had suffered what appeared to be a lightning strike - it was actually an electrical discharge from a high voltage power transmission line. A tree grew tall enough to contact the line, conducting power to the ground close to the home.

Moisture under the garage floor slab vaporized, exploding the floor, sending the car up through the garage roof.

Electricity traveled across from the garage, apparently following tree roots, up an iron entry stair railing, over to aluminum siding (all the aluminum pop rivets melted and all of the the siding corner trim pieces fell to the ground), around the siding to a metal outdoor hose bib to metal water piping.

Inside the building the water pipe was fused and melted, causing a basement flood.


Continue reading at OTHER CAUSES of PIPE PITTING: pH & HCO3 LEVELS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.






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LEAK INSPECTION of WATER SYSTEMS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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