If you've read about it, you're aware of the potential health threat posed by some new faucets.
Here's the problem in a nutshell. Sand-cast brass is an amalgamation of zinc, tin, copper and lead. Lead's role is to add malleability to the mix. Without it, or something very much like it, sand-cast brass cannot be milled to critical tolerances. Most sand-cast faucets contain 5% lead, with 8% marking the Environmental Protection Agency limit.
While these are relatively low numbers, the casting process actually moves the percentage upward. As molten brass cools in its casting, the lead is drawn in, by capillary attraction, to the center, which cools last. This places most of the lead right where the milling is done, which is good, and where the water flows, which is bad. When a faucet is new, water left in contact with the brass for prolonged periods can leach the surface lead from brass, accumulating concentrations many times greater than established safe limits.
While the threat is real, probably few of us ingest much lead in this fashion. First, a dwell time of six to eight hours of continuous contact is required for any significant leaching to occur. And second, almost all surface lead is leached from the brass in the first month or two of use. Experts seem to agree that if you avoid drinking a faucet's first few ounces after a long dwell time, you're pretty safe.
So how will manufacturers meet new lead standards? Some already do. Those using brass-bar stock, instead of sand-cast brass, start with a lead content between 1.5% and 3%. Bar stock has a smooth surface, while sand-cast brass is usually rough.
Still, not every design can use bar stock, which leaves some manufacturers experimenting with lead substitutes. A likely choice is bismuth, which occupies a space next to lead on the periodic table and shares many of its characteristics. Other manufacturers are testing synthetic coatings that would seal the surface.