Cal. Civ. Code § 37.111.327

(1) An adequate and safe wastewater system must be provided for conveying, treating and disposing of all sewage. Immediate measures must be taken to alleviate health and sanitation hazards caused by wastewater at the bed and breakfast establishment when they occur.
(2) A wastewater system has failed and requires replacement or repair if any of the following conditions occur:
(a) the system fails to accept, treat or dispose of wastewater as designed;
(b) effluent from the wastewater system contaminates a potable water supply or state waters; or
(c) the wastewater system is subjected to mechanical failure, including electrical outage, or collapse or breakage of a septic tank, lead line or drainfield line.
(3) Extension, alteration, replacement or new development of any wastewater system must be done in accordance with all applicable local laws and ARM Title 17, chapter 36, subchapters 1, 3 and 6, which cover the minimum standards for individual, shared or multiple user wastewater systems, as regulated by the Montana department of environmental quality.
(4) Disposing of discharged liquid wastes from sinks, showers, toilets or baths on the ground surface is prohibited. Such waste must be discharged into the wastewater system serving the bed and breakfast establishment or into an alternate system approved by the regulatory authority.
(5) Mop water or heavily soiled cleaning water may not be disposed of in any sink other than a mop or utility sink or a toilet.
(6) The department hereby adopts and incorporates by reference ARM Title 17, chapter 36, subchapters 1, 3 and 6 which set rules for subdivisions and on site subsurface wastewater treatment. Copies of the above rules may be obtained from the Department of Public Health and Human Services, Food and Consumer Safety Section, P.O. Box 202951, Helena, MT 59620-2951, or the Department of Environmental Quality, Permitting and Compliance Division, P.O. Box 200901, Helena, MT 59620-0901.