TL;DR: Types of Copper Pipes and Their Uses
- Type K: Thickest, best for underground water lines
- Type L: Versatile, used for interior plumbing and HVAC
- Type M: Thinner, best for budget-friendly indoor systems
- Type DWV: For drain, waste, and vent—not for pressure use
- Rigid vs Flexible: How they differ and where they’re used
- Best for: Interior use, high pressure, outdoor, drain lines
- Color codes: Green (K), Blue (L), Red (M), Yellow (DWV)
Why Copper Pipes Are Still Used in Plumbing
Copper pipes remain popular in plumbing systems because they last a long time and resist corrosion. They work well for hot and cold water and are safe for drinking. Copper competes with plastic pipe options like PEX and PVC.
Overview of the 4 Main Types of Copper Pipes
Copper pipe types vary by wall thickness and use. Knowing the difference helps you choose the right one for your job.
- Type K
- Type L
- Type M
- DWV
Type K Copper Pipe: What It’s Used For
Type K has the thickest wall and holds up well under pressure. It works best for underground water service and main lines.
It comes in hard and soft forms. Color code: Green. It costs more due to its thickness.
Type L Copper Pipe: The Most Common Residential Choice
Type L has a medium wall thickness. It is strong enough for most indoor plumbing and heating systems. It also works for some outdoor use.
Available in rigid and flexible copper tubing. Color code: Blue. Meets most building codes.
Type M Copper Pipe: Budget-Friendly But Limited
Type M has the thinnest wall of any pressurized copper pipe. It is often used for low-pressure indoor plumbing.
Not ideal for high-demand systems or outdoor use. Color code: Red. Costs less but wears out faster.
DWV Copper Pipe: For Drain, Waste, and Vent Systems
DWV copper is not for water pressure. It has very thin walls and is mostly phased out. It is now often replaced by plastic pipe.
Color code: Yellow. Used for waste lines only.
Type L vs Type M Copper Pipe: What’s the Difference?
| Feature | Type L | Type M |
|---|---|---|
| Wall Thickness | Medium | Thin |
| Color Code | Blue | Red |
| Pressure Use | Medium/High | Low Only |
| Cost | Higher | Lower |
| Applications | General Use | Budget Indoor |
Hard Copper vs Soft Copper: What’s the Difference?
Rigid copper comes in straight lengths and needs fittings. Flexible copper comes in coils and bends around corners.
Types K and L come in both forms. Use flexible pipe in tight or curved areas.
Which Type of Copper Pipe Should You Use?
Choose the type based on your plumbing job:
- Type K for underground mains
- Type L for general interior plumbing
- Type M for low-pressure, budget-friendly jobs
- DWV for drain lines only
- Always check your local plumbing codes.
Pros and Cons of Copper Pipe Types
Type K
- Pros: Long lifespan, handles high pressure
- Cons: High cost, harder to install
Type L
- Pros: Strong, meets code, long life
- Cons: More expensive than Type M
Type M
- Pros: Affordable, easy to install
- Cons: Not as durable, limited use
DWV
- Pros: Light, easy to cut
- Cons: Not rated for pressure, rarely used now
FAQs About Copper Pipe Types
What’s the best copper pipe for water lines?
Type L is most commonly used for indoor water lines.
Can I use Type M for hot water?
Yes, but only in low-pressure systems. Type L is safer for hot water over time.
How do I know which type I have?
Check the color and markings on the pipe. Blue = Type L, Red = Type M.
Do building codes allow Type M copper?
In some areas, yes. But many codes prefer or require Type L for pressure lines.
Is rigid or flexible copper better?
Rigid is more common, but flexible works well in tight spaces or remodels.
Choose the Right Copper Pipe for Your Plumbing Job
Each copper pipe type serves a purpose. Know your water pressure, pipe location, and local code before buying.
For help replacing or installing copper pipes, call Apollo Plumbing. We serve Everett, WA and surrounding areas. Our ready right now plumbers handle copper repair and repipe jobs with precision and care.
