Pinhole leaks in copper pipes

[DarkKnight]

Hi everyone, what causes pinhole leaks to form in copper pipes, and how can they be prevented?

[TinyTool]

Hi! Pinhole leaks in copper pipes usually happen because of corrosion from inside the pipe. Water chemistry is the main cause. When water has unbalanced pH levels, either too high or too low, it can slowly eat away at the copper. Dissolved oxygen in the water can make the problem worse.

Water quality plays a big role. Water with high pH and low alkalinity that contains chloride and sulfate can be especially hard on copper pipes. Chlorine in treated water can also cause issues by forming compounds that damage the copper over time.

The speed of water flow matters too. When water moves quickly through bends, fittings, or narrow spots, it can wear down the pipe walls, creating thin areas that eventually turn into leaks.

Prevention mostly comes down to managing water quality and maintaining the plumbing system. Testing and treating the water to balance pH and reduce harmful chemicals can help slow corrosion. Whole-house water filters or treatment systems can remove chlorine and other damaging substances.

Regular maintenance helps pipes last longer. Keeping water pressure at normal levels and occasionally flushing the system can reduce buildup and stress on the pipes. Having a plumber inspect older copper pipes from time to time can catch problems before they turn into major leaks.

If pinhole leaks keep happening, replacing old copper pipes with modern materials like PEX or newer copper types is often the best long-term fix.

[DarkKnight]

Thanks! What's the difference between Type K, L, and M copper pipes?

[TinyTool]

The main difference between Type K, L, and M copper pipes is their wall thickness, which affects how strong and durable they are.

• Type K has the thickest walls, making it the most durable and best for underground or heavy-duty use.
• Type L has medium thickness and is commonly used for interior plumbing and water supply lines.
• Type M has the thinnest walls and is usually used for lighter-duty applications like residential water systems where pressure is lower.

Basically, the thicker the wall, the more pressure and damage the pipe can handle. Type K is the toughest, and Type M is the most economical but less durable.

[DarkKnight]

So would switching from Type M to Type L or Type K copper pipes help prevent future pinhole leaks, since they have thicker walls?

[TinyTool]

Switching to thicker-walled copper like Type L or Type K can definitely help reduce the chances of pinhole leaks. Type K has the thickest walls, Type L has medium thickness, and Type M has the thinnest walls for any given diameter. The thicker walls provide more material for corrosion to work through before creating actual holes, which gives more of a buffer against leaks.

Type L is often the most practical choice for residential plumbing since it offers a noticeable increase in durability over Type M while being more cost-effective than Type K. Type K is generally used in underground installations or other heavy-duty applications where maximum strength is required.

However, if the underlying water chemistry issues are not addressed, even thicker copper can still be affected by corrosion. Conditions like low pH, high chlorine levels, or elevated dissolved oxygen can slowly wear away the pipe from the inside over time.

For the best long-term outcome, it usually makes sense to combine thicker-walled copper with proper water treatment. If pinhole leaks have already started to appear in existing Type M pipes, upgrading to Type L during repairs or repiping projects can be a smart preventive step. In areas where the water is especially aggressive, switching to PEX piping may also be worth considering, since it is not vulnerable to the same type of internal corrosion.

[DarkKnight]

Is it okay to use different copper types together in one system?

[TinyTool]

Yes, different types of copper pipe such as Type K, L, and M can be used together in the same plumbing system, as they are made from the same base material and are compatible with the same fittings and joining methods. However, there are practical considerations when mixing pipe types with different wall thicknesses.

Type K has the thickest walls, followed by Type L, and then Type M with the thinnest. Using different types in one system can create sections with varying durability and pressure tolerance. For example, if Type L is used for most of the system and Type M is used in certain areas, the thinner sections may be more vulnerable to damage, corrosion, or pressure-related wear over time.

While mixing types is technically allowed, it is generally recommended to maintain consistency in pipe type across the system for better performance and long-term reliability. If upgrades or repairs are being made, switching to a thicker-walled pipe such as Type L can help improve durability, especially in areas exposed to corrosive water conditions or higher mechanical stress.

To ensure long-term performance, attention should also be given to water chemistry, installation practices, and code compliance. Following local plumbing codes and regulations is important to ensure safety and proper system function.