What Causes Pipe Corrosion and Breakage?

Wondering if your home is suffering from early pipe corrosion? This can be a serious concern, leading to the need for a whole-house repiping. Find out why pipes corrode, how to prevent or slow corrosion, and what to look out for as your pipes age.

What Causes Pipe Corrosion?

Problems with pipe integrity are usually exacerbated by multiple factors working together. While older plumbing systems are usually more at risk than newer systems for obvious reasons, even new pipes can show signs of corrosion as soon as two years after installation if the right conditions exist. You may find several of the factors that exacerbate corrosion to be surprising. For example, some of the cleanest drinking water in the United States also has a chemical makeup that is extremely hard on pipes, and some of the most popular drain cleaning products are exceptionally harsh and known to cause pipes to corrode.

The following are common causes of corrosion:

Low pH

Ph measures water acidity, ranging from zero (most acidic) to 14 (most alkaline). A pH of 7 represents the neutral pH.

If you have copper pipes, you need to be concerned about the pH of your water. If your pH is 8 or higher (meaning more alkaline and not acidic), a film of copper oxide will form on the inside of your pipes, slowing or minimizing corrosion. However, if your water pH is neutral or acidic, the copper oxide barrier dissolves, leaving your copper pipes vulnerable to accelerated corrosion.

What happens? Pinhole leaks throughout the copper pipe plumbing system.

Oxygen + Water Temperature

Your water system is constantly being replenished with oxygenated water. That means air has been dissolved into the water, comprised of approximately 30% oxygen and 70% nitrogen. Nitrogen is non-corrosive, but oxygen corrodes metal through a process called oxidation.

This is when the metal converts to oxide (rust), and the metal thins and weakens as more and more of it is rusted. As corrosion continues, three things happen.

One, rust accumulates inside your pipes. Rust is not smooth, and the nooks and crannies in this uneven surface attracts and captures impurities in the water, causing build up inside your pipes that looks like this (see picture to the right).

Two, the metal of your pipes thins, becoming vulnerable to breakages.

Three, pinhole cracks develop, or, if you experience a shift in the earth or pressure on the weakened pipes, pipe breakages happen.

Wanna speed up the corrosion process? (Of course you don’t.) The higher your water temperature, the faster oxidation happens. We see more corrosion in hot water lines than cold water lines for this very reason.

Water Velocity is Too High

If you have a "closed loop" piping system, erosion corrosion (I know, it sounds like a made up term, but it’s real) can happen due to flow obstacles like excess solder (if joints were not soldered properly).

Chemical Drain Cleaners

Chemical drain cleaners may burn a hole through whatever is clogging your pipes, but they also burn holes in pipes. See our post about what to use and not to use when cleaning drains to understand why chemical drain cleaners are so bad for your pipes and what types of drain cleaners are most effective and easy on your pipes.

But Aren’t Copper Pipes Invincible?

Contrary to popular belief, copper pipes don’t last forever. Copper is the most widely used material for plumbing systems and for domestic water supply since 1963. In that time, over 5.3 million miles of copper pipes have been installed, Approximately 80 percent of all U.S. buildings have copper pipes in them somewhere.

Unfortunately, copper piping has been found to be vulnerable to corrosion when particular conditions exist. For example, pinhole leaks occur when internal pitting corrosion happens. If we can identify internal pitting corrosion before those leaks begin to appear, we can make appropriate changes and repairs, saving homeowners and business owners large sums of expenses (and preventing extensive water damage from widespread pinhole leaks throughout the system).

Three Types of Copper (Pitting) Corrosion

Type I Copper Pitting Corrosion

Type I copper pitting corrosion typically happens in homes or businesses with hard or moderately hard waters exhibiting a pH of between 7 and 7.8. This type of corrosion typically happens in cold water lines. If not caught in time, it usually results in pipe breakage or pinhole leaks.

Type II Copper Pitting Corrosion

Type II copper pitting corrosion occurs only in systems with water with a pH below 7.2 and hot water with temperatures of over 140° F. The type of corrosion pitting is not as extensive as Type I, but still often results in pipe failure.

Type III Copper Pitting Corrosion

Type III copper pitting corrosion typically occurs in cold water that registers a pH above 8.0. This type of corrosion is less likely to cause pipe breakage, but shows itself in blue-tinged water, byproduct releases and pipe blockage problems due to internal corrosion of the pipes.

Galvanized Steel Pipes

While galvanized steel pipes are no longer used in homes, galvanized pipe was the most commonly used piping material prior the 1960’s. It’s still found in wells, and is found in a lot of older homes. While galvanized steel was coated with zinc (which slows corrosion), it has been found to be very vulnerable to corrosion over time and is no longer regarded as a wise piping choice.

Galvanized pipe is known to have the following problems:

• Reactions to minerals present in the water, resulting in mineral build up inside the pipes.
• Electrolysis, which is a reaction to contact with other metals (i.e. when connected to a section of copper or brass piping or fittings) that results in galvanic corrosion.
• Corrosion from hard water.

Most homes no longer have galvanized steel piping. If you suspect your older home has galvanized steel pipes, you would be wise to get your pipes checked preemptively to prevent a nightmare situation of pipe breakage and water damage to your home or business.

Signs of Pipe Corrosion

If your water is discolored (usually brown), or you have low water pressure, or you are finding signs of leaks, you may have failing pipes due to pipe corrosion. If your home was built in the 1960s or before, you definitely want to have it checked for corrosion.

Charlotte Pipe Repair Solutions

If you discover you have corrosion inside your pipes, you will want to speak with us about repiping and targeted repair options, including trenchless repairs, partial repiping and whole house repiping. We understand that you want to protect your investment without breaking the bank, and we’ll discuss all possible options, including preventative measures you can take to minimize future damage.

Give us a call today at 704.846.5371 to find out how we can help you protect your home or business. We look forward to working with you!

Article Summary

Quick question & answer: How is pipe corrosion caused?

Signs of pipe corrosion occur as early as two years post-installation. A neutral or acidic pH of water dissolves the copper oxide barrier of pipes, making them vulnerable to accelerated corrosion, resulting in pinhole leaks. In addition, the higher your water temperature is, the faster oxidation happens, which corrodes metal, therefore putting hot water lines at higher risk for corrosion.