DZR Brass: What It Is, How It Works, and When to Specify It

Dezincification-resistant (DZR) brass is the alloy most plumbing OEMs default to for parts that have to survive decades of contact with potable water. This is a short explainer of what DZR brass actually is, why dezincification happens, and when it makes sense to specify the more expensive DZR grades over standard brass.

What dezincification is

Standard brass alloys contain roughly 60–62% copper and 38–40% zinc. In contact with water — particularly soft, acidic, or chlorinated water — zinc preferentially leaches out of the alloy over time. What's left behind is a copper-rich porous structure that has little mechanical strength. The part still looks like brass, but it can no longer hold pressure. Twenty years into service, a plumbing fitting that looked fine yesterday springs a leak.

How DZR brass works

DZR alloys — CW602N (CuZn36Pb2As) and CW724R (CuZn21Si3P) being the two main grades — modify the brass chemistry in two ways. They lower zinc content (especially in CW724R, which uses silicon to replace some of the zinc), and they add small amounts of inhibitor elements like arsenic that suppress the zinc-leaching mechanism. The result is a brass that behaves the same under normal use but doesn't dezincify over time.

CW602N is "low-lead DZR brass" and is the most common European drinking-water alloy. CW724R is "lead-free silicon brass," is also DZR, and is the safer default for any new program that needs to clear emerging low-lead regulations (NSF 372, California Proposition 65, EU drinking-water directives).

When to specify DZR

Specify DZR brass for any plumbing or water-management part that will sit in contact with water for years — drinking-water fittings, valve bodies, manifolds, water-meter bodies, fire-hydrant parts, and irrigation fittings. Specify it especially in markets with soft, chlorinated, or saline water (UK, parts of northern Europe, coastal regions).

Specify standard brass (CW614N / CW617N) for non-water applications — pneumatics, HVAC, gas, electrical — where the DZR premium isn't earned by service life.