The neurotoxic element may be lurking in your pipes, window frames—even garden plants. What to look out for, especially if you have kids crawling around. If you live in a city, it's worth getting professional testing—home testing kits have been found to return up to 50 percent false negatives. If significant levels are found, here's where they might come from.
Water pipes and solder in older homes often contain lead; even new fixtures can be up to 8 percent lead. (A federal law lowering the limit to 0.25 percent takes effect in 2014.) The oft-recommended fix of running the tap for several minutes is wasteful and not always effective; better to install an NSF-approved filter at the tap.