If the tenants have been living in the premises for more than one year, they are entitled to 60-days notice to terminate. If they have failed to pay rent, you can serve them with a 3-day notice to pay rent or quit. Likewise, if they are using drugs and creating a nuisance, you can serve them with a three day notice to quit. The notices must be properly served. It is unclear from your post how you served these notices. It is also unclear why you served a 30-day notice after the original 60-day notice expired. Regardless of which notice you serve, if they do not move out in line with the notice, you will have to file an unlawful detainer lawsuit against them.
I would be happy to discuss this matter with you. I have 20 years experience representing landlords and property managers against tenants. I have handled many cases in San Mateo.
I am licensed to practice law in the state of California only and this response is provided as general information only. It is not intended to be legal advice. Legal advice must be based on the specific facts of a particular situation, and by this forum is not appropriate for discussion of specific, exact facts or lawyer-client privileged communications. Contact a lawyer for specific advice. My answer to your question on AVVO does not create an attorney-client relationship.