Avoiding lead poisoning

• In the morning, flush the tap water so that only cold water is used for cooking etc.
• Only use cold water for consumption (heating if needed), so it gets less lead from solder or pipes. (I read that lead is still used in some plumbing parts.)
• Don't have them chewing on old lead paint on windowsills.
• Testing water with a lead test kit is an idea.
• For more info, see wikipedia on "lead poisoning", under the section "prevention".