Lead-Free Brass & Dezincification.

TL;DR.

Last updated: October 2026

Thick castings and an easy-machining alloy.

The old brass valves in your walls earned their reputation honestly. They were cast thick — heavy bodies with real wall section — and they were made from brasses that contained a few percent lead. That lead was there for one metallurgical reason: machinability. It let the brass cut cleanly on the lathe, so threads came out crisp and valve seats sealed the first time. The result was a valve that installed in an afternoon and then sat in the wall for forty years doing its job.

None of that was magic. It was a good alloy, generous castings, and an era when fittings were overbuilt because nobody had figured out how to build them cheaper yet. When you pull one of those old valves in a repipe, the weight in your hand tells the whole story — and yes, old brass is still brass. Brass plumbing fittings, explained.

2011: 0.25% weighted average. That is the whole law.

In 2011, Congress passed the Reduction of Lead in Drinking Water Act — Public Law 111-380, signed on January 4, 2011 — as an amendment to the Safe Drinking Water Act. It redefined what "lead free" means for plumbing: instead of the old allowance of up to 8% lead, the wetted surfaces of pipes, pipe fittings, plumbing fittings, and fixtures could contain no more than a weighted average of 0.25% lead. The law took effect on January 4, 2014, and it included a statutory formula for calculating that weighted average.

A few plain facts around it: solder and flux stayed at their existing 0.2% lead limit. The law did not require anyone to rip out already-installed equipment — it governs what gets sold and installed. And the products that meet the new number are marked and certified to standards like NSF/ANSI 61 and NSF/ANSI 372, which is how you can tell a compliant fitting on the shelf. That is the law, stated plainly, with nothing added.

New recipes for the new number.

To hit 0.25%, the brass industry reformulated. Low-lead brasses replaced the old free-cutting grades in drinking-water fittings. DZR brass — dezincification-resistant brass, with small inhibitor additions of elements like arsenic, tin, or phosphorus — became the standard answer for valves and fittings that live in water. Silicon brasses showed up too, machining well without the lead.

This is worth saying directly: the metal did not get worse. It got different, on purpose, to meet a legal number — and the new alloys are engineered for exactly the job the old ones did. The diagram above shows the DZR idea: a tight, uniform alloy structure where the zinc stays bonded in the metal instead of leaching out.

Zinc leaves; porous copper stays.

Dezincification is a material fact plumbers already know, and here it is in plain language. In brasses with more than about 15% zinc, aggressive water — slightly acidic or alkaline, low flow, warm — can selectively pull the zinc atoms out of the alloy. The copper stays behind, but it is left as a porous, spongy structure with little of the original strength. The valve keeps its shape and dimensions while losing its integrity, which is why the failure surprises people.

Here is what it looks like in the field: white powdery mineral deposits on the outside of the fitting, dull reddish spots under the original yellow surface where the copper-rich layer shows through, and water weeping from the valve body or around the stem. Engineers test resistance to it with the ISO 6509 method — a 24-hour soak in a hot cupric chloride solution, with strict limits on how deep the attack may go. DZR brass is built to pass that test. This is metallurgy, not a scandal: old brass in good water lasts indefinitely, and new DZR brass in tough water holds up. Your plumber decides what stays in the wall — this page just tells you what is happening inside the metal.

Old brass is still brass.

None of this changes what I buy. Old valves, new valves, fittings from before the law and after it — brass is brass, and it sorts by the same tests on the home test kit: color, magnet, weight, and the file scratch. A dezincified valve still weighs what it weighs, and the honest sorting happens at the scale. If you are pulling brass in a repipe or a cleanout, the pile is the pile — photograph it and call. Selling brass scrap, the plain-English way.

Where to go next.

Brass Guide — back to the hub: every brass guide, organized by track. Brass Plumbing Fittings — the valves and fittings themselves, in the dictionary. How to Identify Brass — the home test kit for the pile from the repipe. Yellow Brass — the gold-yellow workhorse alloy.

Lead-free brass questions, answered.

I learned the law so I could speak the trade's language.

I am new to brass — I have said that from the start. But I learned the 2011 law cold, because the plumbers I buy from know it cold, and a buyer who does not know the material is just a guy with a truck. The old valves lasted because they were built like tanks. The new ones are engineered for a legal number. Both are brass, and I buy both.