Expert Support
Type K vs. Type L vs. Type M Copper Tubing – Which Should You Choose?
Choosing the right copper tubing for your plumbing or HVAC job isn’t always straightforward. One of the most common questions we get is:
“What’s the difference between Type K, Type L, and Type M copper tubing?”
Let’s break it down so you know exactly what to order.
Type K Copper Tubing
- Thickest wall of the three types
- Ideal for underground water lines and high-pressure systems
- Used in both commercial and residential plumbing
- Available in coils and straight lengths
Pro Tip: Type K is commonly specified by city codes for underground service lines.
Type L Copper Tubing
- Medium wall thickness
- Most commonly used for interior plumbing
- Versatile for hot/cold water lines and HVAC systems
- Also available in rigid and flexible formats
Pro Tip: Type L strikes the best balance of strength, price, and ease of installation.
Type M Copper Tubing
- Thinnest wall
- Used in low-pressure residential plumbing
- Not approved for some jurisdictions due to its thinner walls
- Lower cost — good for budget-conscious jobs where code allows
Summary Table
| Type | Wall Thickness | Common Use |
| K | Thickest | Underground, high-pressure |
| L | Medium | Interior plumbing, HVAC |
| M | Thinnest | Budget residential use |
Still not sure which type you need?
Visit our collection pages for Type K, Type L, and Type M copper tubing — or contact us and we’ll help you choose the right one.