If no water has been drawn for six or more hours, then turning on the tap and letting it run for 45 seconds or more would flush out all the water that has been sitting in the pipe. It is when water has had a long contact time with the pipe, sittings or fixtures containing lead that there is a danger of lead leaching ino the water..So water used for drinking or food preparation after flushing the lines this way should have have a risk of lead.
Other steps are: having your water tested for lead, or switching to bottled water for drinking. Some water filters may remove lead, but please read lables on filters to see if they are certified for lead removal.