Cal. Civ. Code § 43-32-27

A cause of action may arise in favor of a lessee and against a lessor of residential property, including a manufactured or mobile home community owner, for retaliation by the lessor against the lessee if the lessor increases rents above fair market value; if the lessor decreases electric, gas, water, or sewer services; or if the lessor gives the lessee notice to vacate the premises when such notice is not based upon a breach of the terms of the lease; subsequent to any of the following special events:
(1) The lessor has received written notice from the lessee or a governmental agency that the lessee has complained to a governmental agency charged with responsibility for enforcement of a building or housing code violation applicable to the premises and materially affecting health and safety, and the complaint is determined to be reported in good faith; or
(2) The lessee has given written notice to the lessor of a condition requiring repair pursuant to § 43-32-9; or
(3) The lessee has organized or become a member of a tenant's union or organization.
It shall be a defense to this cause of action that the notice to vacate the premises was given by the lessor more than one hundred eighty days after the occurrence of a special event. The failure of the lessor to renew any written lease prior to or upon its expiration, is not retaliation.