What Is Pitting Corrosion in Pipes?
Pitting corrosion is a type of localized metal degradation that occurs when small but deep cavities form on the surface of a pipe. These pits can eventually penetrate the pipe wall, leading to leaks or structural failure.
Unlike general corrosion, where the entire surface of a pipe deteriorates at a consistent rate, pitting corrosion is unpredictable and difficult to detect. The pits may be small on the surface but can extend deep into the material, making them a significant threat to plumbing systems.
This type of corrosion is particularly problematic because it can weaken pipes without visible warning signs. By the time leaks or bursts occur, the damage may already be extensive, requiring costly repairs or even a full repipe of your home.
What Causes Pitting Corrosion in Pipes?
Several factors contribute to pitting corrosion in plumbing systems. The most common causes include:
- Water Chemistry: Hard water is the most common cause of pitting. Water supplies with high levels of chlorides, acidity, or oxygen can also accelerate the corrosion process.
- Sediment and Contaminants: Grit, sand, and other particles can wear away protective coatings on metal pipes, exposing them to corrosion.
- High Water Velocity: Fast-moving water, especially at pipe bends and fittings, can erode the pipe's surface, making it more vulnerable to pitting.
- Poor Installation or Manufacturing Defects: Outdated pipe materials such as galvanized plumbing, improper welding, or installation errors can leave pipes more susceptible to corrosion.
Understanding these causes can help homeowners take preventative measures to extend the life of their plumbing system.
Which Pipe Materials Are Most Susceptible to Pitting Corrosion?
Certain pipe materials are more prone to pitting corrosion than others. We have listed the three most vulnerable materials:
- Copper Pipes: While durable, copper is highly susceptible to pitting corrosion, especially when exposed to high chloride levels or hard water. This can lead to the formation of pinhole leaks in your copper pipes.
- Galvanized Steel Pipes: These pipes have a zinc coating to protect against corrosion. Over time, the zinc coating can wear away, leading to rust and pitting.
- Stainless Steel Pipes: Though resistant to many forms of corrosion, stainless steel can still develop pitting in environments with high chloride exposure, such as swimming pools or coastal areas.
If your home has older copper or galvanized steel plumbing, you may want to consider repiping with more corrosion-resistant materials.
Are There Corrosion Resistant Pipe Materials?
One of the best materials for avoiding pitting corrosion is PEX (Cross-Linked Polyethylene) tubing.
Unlike copper or steel, PEX does not corrode, rust, or develop pinhole leaks due to pitting corrosion. This makes it a highly durable option for homeowners looking for a long-term plumbing solution.
Additionally, PEX tubing is flexible, which reduces the likelihood of cracking or bursting under pressure or temperature changes. This flexibility also allows for easier installation, as it can be bent around corners without the need for additional fittings.
PEX tubing has a smooth interior surface that prevents sediment buildup, ensuring consistent water flow and reducing the risk of blockages. For homeowners concerned about pitting corrosion, repiping with PEX provides a reliable, low-maintenance solution that extends the lifespan of their plumbing system while improving overall performance.
Contact us to have one of our local repipe consultants provide you with a consultation and quote, either in-home or remotely.
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At Repipe Specialists, we've replaced plumbing damaged by pitting corrosion in homes across the USA using Uponor PEX-A tubing. Our customers consistently share positive feedback about their repipe experiences, often noting that we exceed expectations in:
- Speed: Our repipe crews typically complete a repipe in a day, returning on another day for wall patching.
- Convenience: Through our One-Stop Repipe™ Process, we handle everything from permits, to wall patching, to inspections.
- Cleanliness: Our crews are trained to protect your home while working (we cover all surfaces with protective sheeting), and to clean up fully at the end of each day.
- Peace of Mind: Repipe Specialists is a fully licensed plumber in every state we operate in, and we back all of our repipes with a lifetime warranty.
- Financing programs: To help take the sting out of unplanned repipe expenses, we offer several financing programs.
- Price: As a specialist that performs hundreds of repipes a week, we can deliver high-quality repipes at a lower cost vs generalist plumbers. Our quotes typically range from $4,500 to $15,000 depending on the size and complexity of your project. We have an article that covers repipe cost factors in detail.
Schedule a free in-home consult, and one of our local repipe consultants will explain all your repipe options and provide you with a written, fixed-price quote.