Cal. Civ. Code § 101.149

101.149 Carbon monoxide detectors.
(1) Definitions. In this section:
(ag) “Bed and breakfast establishment” has the meaning given in s. 97.01 (1g).
(am) “Carbon monoxide detector” means an electronic or battery-operated device or system that sounds an alarm when an unsafe level of carbon monoxide is in the air.
(as) “Fuel-burning appliance” means a device that burns fossil fuel or carbon-based fuel and that produces carbon monoxide as a combustion by-product.
(b) “Residential building” means a tourist rooming house, a bed and breakfast establishment, or any public building that is used for sleeping or lodging purposes. “Residential building” does not include a hospital or nursing home.
(c) “Sleeping area” has the meaning given in s. 101.145 (1) (b).
(cm) “Tourist rooming house” has the meaning given in s. 97.01 (15k).
(d) “Unit” means a part of a residential building that is occupied by one or more persons as a home, residence, or sleeping place.
(2) Installation requirements.
(ac) Carbon monoxide detectors required. Except as provided in sub. (5), the owner of a residential building shall provide carbon monoxide detectors at the locations specified in par. (ax) as required under pars. (ag) to (at).
(ag) Fuel-burning appliances. Carbon monoxide detectors shall be provided in units that contain a fuel-burning appliance.
(aL) Forced-air furnaces. Carbon monoxide detectors shall be provided in units served by a fuel-burning, forced-air furnace, except that carbon monoxide detectors are not required in a unit if a carbon monoxide detector is provided in the first room or area served by each main duct leaving the furnace and one of the following is satisfied:
1. The carbon monoxide alarm signals are automatically transmitted to all units served by the furnace and to a designated location at a facility staffed by trained personnel on a continuous basis where alarm and supervisory signals are monitored and facilities are provided for notification of the fire department.
2. In addition to the first room or area served by each main duct leaving the furnace, a carbon monoxide detector is installed in every 4th unit on the same floor as that first room or area.
(ap) Fuel-burning appliances outside of units. Carbon monoxide detectors shall be provided in units located in residential buildings that contain fuel-burning appliances, except as follows:
1. Carbon monoxide detectors are not required in units where there are no openings between the fuel-burning appliance and the unit through which carbon monoxide can get into the unit.
2. Carbon monoxide detectors are not required in units where a carbon monoxide detector is provided in one of the following locations:
a. Between the fuel-burning appliance and the unit.
b. On the ceiling of the room containing the fuel-burning appliance.
(at) Private garages. Carbon monoxide detectors shall be provided in units in buildings with attached private garages, except as follows:
1. Carbon monoxide detectors are not required where there are no openings between the private garage and the unit through which carbon monoxide can get into the unit.
2. Carbon monoxide detectors are not required in units located more than one story above or below the private garage.
3. Carbon monoxide detectors are not required where the private garage connects to the building through an open-ended corridor.
4. Where carbon monoxide detectors are provided between openings to the private garage and units, carbon monoxide detectors are not required in the units.
5. Carbon monoxide detectors are not required where the private garage has openings designed to provide natural ventilation, or is mechanically ventilated, in accordance with rules for natural and mechanical ventilation in public parking garages promulgated by the department.
(ax) Locations. If required under pars. (ag) to (at), carbon monoxide detectors shall be installed in the following locations:
1. ‘Units.’ In units, outside of each separate sleeping area in the immediate vicinity of the sleeping rooms.
2. ‘Sleeping rooms.’ In sleeping rooms, if a fuel-burning appliance is located within the sleeping room or its attached bathroom.
(d) Certification. Any carbon monoxide detector that bears an Underwriters Laboratories, Inc., listing mark or similar mark from an independent product safety certification organization satisfies the requirements of this subsection.
(e) Manufacturer directions and specifications. The owner shall install every carbon monoxide detector required by this subsection according to the directions and specifications of the manufacturer of the carbon monoxide detector.
(3) Maintenance requirements.
(a) The owner of a residential building shall reasonably maintain every carbon monoxide detector in the residential building in the manner specified in the instructions for the carbon monoxide detector.
(am) If any person certified under s. 101.12 (4) or 101.14 (4r) gives written notice to an owner of a residential building that a carbon monoxide detector in the residential building is not functional, the owner shall provide, within 5 days after receipt of that notice, any maintenance necessary to make that carbon monoxide detector functional.
(b) An occupant of a unit in a residential building may give the owner of the residential building written notice that a carbon monoxide detector in the residential building is not functional or has been removed by a person other than the occupant. The owner of the residential building shall repair or replace the nonfunctional or missing carbon monoxide detector within 5 days after receipt of the notice.
(c) The owner of a residential building is not liable for damages resulting from any of the following:
1. A false alarm from a carbon monoxide detector if the carbon monoxide detector was reasonably maintained by the owner of the residential building.
2. The failure of a carbon monoxide detector to operate properly if that failure was the result of tampering with, or removal or destruction of, the carbon monoxide detector by a person other than the owner or the result of a faulty detector that was reasonably maintained by the owner as required under par. (a).
(4) Tampering prohibited. No person may tamper with, remove, destroy, disconnect, or remove batteries from an installed carbon monoxide detector, except in the course of inspection, maintenance, or replacement of the detector.
(5) Exception. Subsections (2) and (3) do not apply to the owner of a residential building if all of the fuel-burning appliances in the residential building have sealed combustion units that are covered by the manufacturer’s warranty against defects.
(6) Rules. The department shall promulgate rules establishing a procedure under which the owner of a residential building may apply to the department for a waiver of the requirements under sub. (2).
(7) Inspection. To ensure compliance with subs. (2) and (3), the department or a person certified under s. 101.12 (4) or 101.14 (4r) may inspect the common area of residential buildings and may inspect a unit within such buildings at the request of the owner or occupant of the unit to be inspected.
(8) Penalties.
(a) If the department of safety and professional services or the department of agriculture, trade and consumer protection determines after an inspection of a building under this section or s. 97.625 (1g) that the owner of the building has violated sub. (2) or (3), the respective department shall issue an order requiring the person to correct the violation within 5 days or within such shorter period as the respective department determines is necessary to protect public health and safety. If the person does not correct the violation within the time required, he or she shall forfeit $50 for each day of violation occurring after the date on which the respective department finds that the violation was not corrected.
(b) If a person is charged with more than one violation of sub. (2) or (3) arising out of an inspection of a building owned by that person, those violations shall be counted as a single violation for the purpose of determining the amount of a forfeiture under par. (a).
(c) Whoever violates sub. (4) is subject to the following penalties:
1. For a first offense, the person may be fined not more than $10,000 or imprisoned for not more than 9 months, or both.
2. For a 2nd or subsequent offense, the person is guilty of a Class I felony.