Hey Mr. Green,
I really don't want to drink bottled water, because tap water is cheaper and better for the environment. But my house was built in 1940, and the plumbing is of that same vintage. Our local water was tested and found to be safe, but I'm worried that the water from my own pipes may be contaminated with lead. Should I continue to use bottled water?--Eloise in Manhattan Beach, California
Since bottled water can cost 2,000 times more than tap water, you might be better off investing in new pipes, or at least a reliable water filter. Plus, bottled water isn't necessarily cleaner than municipal water; the plastic-encased stuff is often drawn from the same source.
As for the contamination potential of your home's aging pipes, lead is more likely to be found in the water of quite old or somewhat newer houses. Pre-1930s plumbing most often contains lead, though many old pipes may be safe because they've become encrusted with lead-blocking deposits over the years. Newer houses' copper pipes are suspect because, until it was banned in 1986, high-lead solder was used during installation.
To be certain about lead content, find a reliable lab to test your water by contacting the Centers for Disease Control and Prevention (800-232-4636) or the National Lead Information Center (bit.ly/leadinfo), which can also help you deal with other lead sources, like old paint. Lead--and other toxics--can be removed with filters OK'd by NSF International (nsf.org/consumer).
If your faucets have been idle for six hours or more, you can flush out lead by running cold water in the sink for a minute or two and in the bath for five minutes. But that's a lot of wasted water, so it should only be a short-term solution.