When it comes to the material used in home plumbing, water pipe systems have evolved. The plumbing in vintage and historical houses may have been made of iron, steel, or even lead, but these days copper and PVC piping are favored. They’re softer, lighter materials, easier to use and install, long-lasting, recyclable, and less corrosive and reactive.
But no piping is perfect. That’s why you may be seeing green spots on your older copper pipes.
The Meaning Of The Green
Have you ever wondered why the Statue of Liberty is green? Although the internal structure is made of iron and steel, the outside of Lady Liberty is coated with copper. When copper is exposed over time to oxygen in the air as well as the various acidic and basic components of rain, smoke, smog, and weather, it develops a green patina.
Under certain conditions, the same happens to the copper of your water pipes.
The Pain Of Pinhole Leaks
Spots of green appearing on your copper pipe is an indication of pinhole leaks. Water has seeped through small holes in the surface to react with the outside layer, causing circles of patina.
The cause of this pitting is varied. Although copper is relatively unreactive, it is not immune to caustic conditions. Check out these three likely culprits:
- If your local water supply comes from a well, rather than buffered as in most municipal water systems, you may want to check the pH. A pH below 6.5 will cause pitting inside the pipe. More alarmingly, it will also seep lead from old soldered joints.
- Chloramines, a byproduct of the municipal water treatment process, may also be the culprit. Ironically, these compounds took the place of chlorine in the 1990s to comply with new EPA standards.
- Particle corrosion from old pipes or water heaters may also be to blame. Under pressure, these rusty metallic particles can scour and scratch the inside of the pipes.
The Fix Is In
If you’re only seeing a few pinhole leaks, there are plenty of ways to plug them. You can solder, use a repair clamp, choose a chemical sealant, or just replace the length of the affected pipe, all easy fixes for the intrepid DIYer.
Unfortunately, many of the causes of pinhole leaks are out of a homeowner’s control. It’s likely that your copper pipes may be reaching the end of their natural use. Talk to your trusted plumber and consider what’s involved in a whole house re-pipe. Newer PVC materials are far less expensive than copper piping, will save you worry, and last just as long.