Brass

Lead is added to brass on purpose. The workhorse machining grade, C36000, is specified at 2.5 to 3.7% lead, because lead is what lets a cutter run cleanly through the alloy. US law addressed this in the drinking-water path only: Section 1417 of the Safe Drinking Water Act, as amended by the 2011 Reduction of Lead in Drinking Water Act, redefined "lead free" as a weighted average of no more than 0.25% lead across the wetted surfaces of pipes, fittings and fixtures - down from 8% - plus 0.2% for solder and flux. NSF/ANSI 372 certifies that content limit; NSF/ANSI 61 tests what actually leaches. The honest reading is that "lead free" is a ceiling on content, not a claim of zero: EDF measured 9 to 10 ppb of lead from newly installed certified faucets, and reported that 11% of 507 faucets leached more than 3 micrograms on day three of the standard's own protocol. Lead comes off worst when a fixture is new and when water has sat against it, so flushing a few seconds before drawing water to drink or cook, an NSF/ANSI 53 lead-certified filter, or a drinking-water path that bypasses the brass body entirely, are the three things that actually help. Brass is also covered by the FDA Food Code ban on copper alloys touching food below pH 6.

Nothing a kitchen or a bathroom does affects brass structurally - it melts near 900C and holds thread and pressure at boiler temperatures, which is why espresso machines are full of it. Heat matters here only indirectly: hot-water and steam lines run through the same brass fittings, and it is dwell time against the metal, more than temperature, that governs how much lead ends up in the water.

Brass is yellow-gold where copper is reddish, non-magnetic, and noticeably heavy - a magnet distinguishes solid brass from brass-plated steel instantly. Most of the brass in a product is invisible under chrome or nickel plating, so look at an unplated internal thread or into the water passage, where the raw yellow shows. Reddish or pinkish patches on a yellow brass surface are dezincification: zinc has leached out and left porous copper behind. For anything carrying drinking water, ask a brand three specific questions - is there brass or bronze anywhere in the wetted path, is the product certified to NSF/ANSI 372 and NSF/ANSI 61, and does the drinking-water line have its own waterway that never touches the body casting. Look for an "NL", "LF" or lead-free stamp on fittings and a DZR or CR marking where water is aggressive.

Brass is close to indestructible in normal service and tarnishes to a dull brown that is purely cosmetic; lacquered brass eventually flakes its lacquer and looks worse than the bare metal would. The two real failure modes are dezincification in aggressive water, which leaves the casting porous and brittle, and plating wearing through at handled points on razors and levers.

Brass has high scrap value and is one of the most reliably recycled metals - scrap yards buy it by the pound and it is remelted rather than landfilled. It is not a curbside material, so small brass parts inside a discarded appliance usually go wherever the appliance goes.