Brass is usually alloyed with lead to make it easier to cast. By law, faucets sold in the U.S. can't contain more than 8 percent lead, but that lead can contaminate water sitting inside the faucet body for more than a few hours. (Running the tap for a few seconds will flush it out.) California and Vermont have enacted a stricter standard: a "maximum weighted average" of no more than 0.25 percent. For a list of nearly 7,000 faucets that meet this low-lead standard, go to NSF.org/consumer
, or look for fixtures with the label NSF 61-G. rtridge valves differ by faucet make and model; if you ever need to replace one, order it directly from the manufacturer.