I am NOT a CA attorney, but have been involved in similar situations in my own state many times. I have found that a letter (certified mail RRR) that references the lease agreement (dollars to donuts there is a provision in your written lease addressing the matter) and reiterates that 24 hours notice is required for all entry to the property except emergency situations and failure observe your exclusive right to the property may be considered a breach of contract, lead to a civil suit, and could result in damages. termination of the lease agreement and attorney fees being accessed against the LL. BEFORE sending that letter, a face-to-conversation to with the LL politely laying out the similar demands is a good way-ahead..
NOT LEGAL ADVICE. FOR EDUCATION AND INFORMATION ONLY. Mr. Rafter is licensed to practice in the Commonwealth of Virginia and the US Federal Courts in Virginia. His answers to any Avvo question are rooted in general legal principles--NOT your specific state laws. There is no implied or actual attorney-client relationship arising from this education exchange. You should speak with an attorney licensed in your state, to whom you have provided all the facts before you take steps that may impact your legal rights. Mr. Rafter is under no obligation to answer subsequent emails or phone calls related to this matter.
As an initial matter, I think it would be a good idea to have a frank discussion with your land lord about the problem. If that fails, you may have legal remedies for a breach of quite enjoyment. While your landlord does have the right to access the property to make repairs, that right is often limited by the terms of the lease as well as state law. Moreover, any activity which unreasonably denies you the reasonable enjoyment of your property could give rise to claim for breach of quite enjoyment. If the talk with your land lord fails, you should look at the terms of your lease, which likely requires the land lord to give 24 hours notice prior to property entrance, and contact an attorney.