The 4 Types of Copper Pipes You Might Encounter in Construction

From Type K to DWV

copper plumbing in construction of home
Photo: alacatr/ iStock/ Getty Images Plus
copper plumbing in construction of home
Photo: alacatr/ iStock/ Getty Images Plus
Get quotes from up to 3 pros!
Enter a zip below and get matched to top-rated pros near you.
Geo Icon

For many newer home installations, copper pipes are being replaced by flexible PEX (cross-linked polyethylene) given that PEX is much less expensive and not as prone to freezing, but copper pipes are still sometimes used as they are considered an extremely strong building material that has a longer lifespan of up to 70 years. 

Not only are there different types of copper pipes, but the types are indicative of the pipe’s strength and application. Knowing the four main types of copper piping can ensure that you’re installing the right kind for your home and that your pipes will last you for decades to come. 

1. Type K

copper plumbing pieces on blueprint
Photo: DenBoma/iStock/ Getty Images

Type K copper pipes are durable and made to last, due to their thick walls. The thickness of Type K pipes can vary based on the individual pipe’s diameter: for instance, ½-inch Type K pipe has a wall thickness of .049 inches, while ¾-inch has a thickness of .065 inches. Because this type is thicker and heavier, it’s also more expensive, making it a good choice for projects that require heft, such as commercial plumbing, HVAC, city water mains, and underground lines. Type K is available in flexible and rigid forms, and is usually identified by a green stamp.

Best for: City plumbing projects and other underground lines

2. Type L

Considered the most common type of copper piping, Type L copper pipes are often used for interior plumbing, swimming pools, some HVAC projects, and fire protection. These pipes are less expensive than Type K pipes, but are still very strong, with a wall thickness of .045 inches for a ¾-inch diameter. Type L copper pipes are marked with blue and come in both flexible rolls and rigid tubing. If your area has hard water, Type L is a good choice as the minerals won’t wear away at the thicker walls as easily as Type M pipes.

Best for: Interior plumbing, swimming pools and spas

3. Type M

Identified by red markings, Type M is the thinnest copper pipe listed here, with a wall thickness of .032 inches for a ¾-inch diameter pipe or .028-inch thickness for a ½-inch diameter pipe. Type M copper piping is often used for repairs, replacements, and extensions to interior water supply lines (if you need to fix a copper pipe leak, for instance); it is less rigid and easier to work with than pipes with thicker walls, making it a favorite of DIYers. It is also less expensive but is not always allowed by plumbing codes, so check with your local building authority or a local plumber before installing it.

Best for: Repairs or replacements to home water lines, where allowed

4. Copper DWV

DWV stands for “drain-waste-vent”—as that suggests, these pipes are used exclusively in drain and vent lines. You won’t find copper DWV piping in newer homes; many contemporary construction projects rely on ABS plastic or PVC pipes vs. copper. Copper DWV pipes are only suitable for above-ground applications, and are never used in water systems as they only have a wall thickness of .042 inches for a 2-inch pipe and can withstand just 15 psi of pressure. Copper DWV pipes are marked with yellow. 

Best for: Drain-waste-vent pipes for exposed locations or vintage homes that require piping to be consistent with historical choices

Copper Pipe TypeDurabilityUses
Type KVery strong with thick wallsMain water lines, oil, HVAC
Type LStrong with thick wallsMany applications, often used for interior water lines
Type MLess strong, with thinner walls; not allowed in every municipalityRepairs and replacements for interior water lines
DWVThin, incapable of handling high pressureOnly used for drain-waste-vent piping
Need professional help with your project?
Get quotes from top-rated pros.
The homeowners guide to plumbing services
From average costs to expert advice, get all the answers you need to get your job done.
A modern bathroom with a glass shower, a white toilet and a modern sink
May 9, 2025
May 9, 2025
Wondering how much it costs to reroute plumbing? We have the information you need to learn about plumbing vent pipes and cost considerations when installing them.
An elegant bathroom with a minimal shower
May 8, 2025
May 8, 2025
Is the water pressure in your shower lacking? Here are common solutions to increase it so you can enjoy your showers again.
man installing linear drain
May 7, 2025
May 7, 2025
Linear shower drains offer several stylistic options for your bathroom, but they can come at a cost. Keep reading to learn about linear shower drain pros and cons.
Bathroom with glass shower stall and white tiles
May 7, 2025
May 7, 2025
A properly installed shower pan is a crucial part of a leak-free floor. Learn how to install your own shower pan with this handy guide.
Bathroom with a sink and a shower
May 12, 2025
May 12, 2025
Shower pans direct water toward the drain while protecting the substructure. Here are the types of shower pans and how they differ from a base.
white ceramic tile glass shower stall
May 8, 2025
May 8, 2025
Your shower pan is an unsung hero that can prevent leaks and flooding in your bathroom. Learn how to spot a leaking shower pan and ways to fix it.