Cal. Civ. Code § 1941.3

(a) On and after July 1, 1998, the landlord, or his or her agent, of a building intended for human habitation shall do all of the following:
(1) Install and maintain an operable dead bolt lock on each main swinging entry door of a dwelling unit. The dead bolt lock shall be installed in conformance with the manufacturer’s specifications and shall comply with applicable state and local codes including, but not limited to, those provisions relating to fire and life safety and
accessibility for the disabled. When in the locked position, the bolt shall extend a minimum of 13 / 16 of an inch in length beyond the strike edge of the door and protrude into the doorjamb.
This section shall not apply to horizontal sliding doors. Existing dead bolts of at least one-half inch in length shall satisfy the requirements of this section. Existing locks with a thumb-turn deadlock that have a strike plate attached to the doorjamb and a latch bolt that is held in a vertical position by a guard bolt, a plunger, or an auxiliary mechanism shall also satisfy the requirements of this section. These locks, however, shall be replaced with a dead bolt at least 13 / 16 of an inch in length the first time after July 1, 1998, that the lock requires repair or replacement.
Existing doors which cannot be equipped with dead bolt locks shall satisfy the requirements of this section if the door is equipped with a metal strap affixed horizontally across the midsection of the door with a dead bolt which extends 13 / 16 of an inch in length beyond the strike edge of the door and protrudes into the doorjamb. Locks and security devices other than those described herein which are inspected and approved by an appropriate state or local government agency as providing adequate security shall satisfy the requirements of this section.
(2) Install and maintain operable window security or locking devices for windows that are designed to be opened. Louvered windows, casement windows, and all windows more than 12 feet vertically or six feet horizontally from the ground, a roof, or any other
platform are excluded from this subdivision.
(3) Install locking mechanisms that comply with applicable fire and safety codes on the exterior doors that provide ingress or egress to common areas with access to dwelling units in multifamily developments. This paragraph does not require the installation of a door or gate where none exists on January 1, 1998.
(b) The tenant shall be responsible for notifying the owner or his or her authorized agent when the tenant becomes aware of an inoperable dead bolt lock or window security or locking device in the dwelling unit. The landlord, or his or her authorized agent, shall not be liable for a violation of subdivision (a) unless he or she fails to correct the violation within a reasonable time after he or she either has actual notice of a deficiency or receives notice of a deficiency.
(c) On and after July 1, 1998, the rights and remedies of tenant for a violation of this section by the landlord shall include those available pursuant to Sections 1942, 1942.4, and 1942.5, an action for breach of contract, and an action for injunctive relief pursuant to Section 526 of the Code of Civil Procedure. Additionally, in an unlawful detainer action, after a default in the payment of rent, a tenant may raise the violation of this section as an affirmative defense and shall have a right to the remedies provided by Section 1174.2 of the Code of Civil Procedure.
(d) A violation of this section shall not broaden, limit, or otherwise affect the duty of care owed by a landlord pursuant to existing law, including any duty that may exist pursuant to Section 1714. The delayed applicability of the requirements of subdivision (a) shall not affect a landlord’s duty to maintain the premises in safe condition.
(e) Nothing in this section shall be construed to affect any authority of any public entity that may otherwise exist to impose any additional security requirements upon a landlord.
(f) This section shall not apply to any building which has been designated as historically significant by an appropriate local, state, or federal governmental jurisdiction.
(g) Subdivisions (a) and (b) shall not apply to any building intended for human habitation which is managed, directly or indirectly, and controlled by the Department of Transportation. This exemption shall not be construed to affect the duty of the Department of Transportation to maintain the premises of these buildings in a safe condition or abrogate any express or implied statement or promise of the Department of Transportation to provide secure premises. Additionally,
this exemption shall not apply to residential dwellings acquired prior to July 1, 1997, by the Department of Transportation to complete construction of state highway routes 710 and 238 and related interchanges.