Since the OP asked about lead in particular, here is some additional info. The lead in drinking water came primarily from the solder used with copper pipes. This was outlawed in 1986 Safe Water Drinking Act. Here is a link:
Copper & the Environment: Drinking Water Plumbing Systems
While you didn't say where your home is located, it is a pretty safe bet that it doesn't have copper pipes with lead solder. In fact you probably don't have any copper pipes. BTW, when you hear about lead problems in drinking water, it is almost always in older communities and most of the lead in home drinking water comes from pipes within the house.
Basic Information about Lead in Drinking Water | Ground Water and Drinking Water | US EPA
In my opinion, you shouldn't worry about the lead in your drinking water unless your home was built before 1986. In that case, use a Brita water filter for all water that you consume - an all house water filter won't take care of the problem.