Copper Pipe Types K, L, M: A Tustin Guide

2026-01-12

Plumbing Guide

Copper pipe comes in three wall thicknesses — K, L, and M — and the letter is stamped on the pipe. The thickness decides where each type is used and how long it lasts.

Copper Pipe Types K, L, M: A Tustin Guide

The type K

Type K has the thickest wall and is used for underground service and high-pressure lines, and it is the most durable and expensive.

The type L

Type L is the standard for most home supply lines, balancing strength and cost, and it is a common choice for repipes.

The type M

Type M has the thinnest wall and is used for above-ground interior lines where cost matters, and it is more prone to pinholes over time.

The reading

The type is printed along the pipe, and knowing it helps predict how the line is aging. mineral-rich water varies by region, and older neighborhoods still run on aging galvanized or copper lines In Tustin, thin type M lines are often the first to leak.

The pinhole

Thin type M copper is the most prone to pinhole leaks over time. Knowing the type in your walls helps predict when a repipe is coming.

The call

Know the pipe in your walls. Call 888-217-3585 and Tustin Home Plumbing Co will match you with a Tustin pro.

Plumbing in Tustin: what to know

In Tustin, mineral-rich water varies by region, and older neighborhoods still run on aging galvanized or copper lines. Pros in our network know the local quirks and bring the right parts on the first visit.

Across Orange County — from Santa Ana, Irvine and Orange to ZIP codes like 92780, 92782, 92705 — homeowners deal with the same kinds of issues. The tips above apply locally, and when a job goes beyond a quick fix, a vetted local pro is only a call away.

Need a hand in Tustin?

If a plumbing issue is beyond a quick fix, don't wait for it to get worse. Call 888-217-3585 and Tustin Home Plumbing Co will match you with a vetted local pro — usually within minutes. Learn more about plumbing help in Tustin.

Plumbing emergency or urgent repair? Call now.

Call 888-217-3585 and we'll match you with a vetted plumbing pro in Tustin — usually within minutes.

Emergency? Call Now888-217-3585
Emergency? Call Now888-217-3585