Many states have enacted social host liability laws that hold parents and/or legal guardians responsible for any underage drinking events that occur in their homes. California has no such state statute, but The Center for the Study of Law and Enforcement Policy warns that this does not get you off the hook if you allow your underage child and his or her friends to consume alcohol or controlled substances in your home.
You could face misdemeanor charges in any of the following situations:
Your best interests dictate that you check with your town and county officials before allowing your teenager to host a party at your home where you know or suspect that (s)he will serve alcohol and/or that his or her friends will bring some with them. California state law gives cities and counties the option to enact their own social host liability ordinances.
Your town and county likewise have authority to enact Response Costs Recovery ordinances. If your town or county has one, it likely treats underage drinking parties held on private property as public nuisances. You could, therefore, find yourself liable for paying the costs of any police, fire or other emergency services called for in association with your teenager’s at-home party.