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 wallof the three types
Ideal forunderground water linesand high-pressure systems
Used in both commercial and residential plumbing
Available incoilsandstraight 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 forinterior 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 approvedfor 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.
