Cal. Civ. Code § 37.111.114

(1) The local regulatory authority shall issue a restricted-use order to an establishment when:
(a) the Montana Department of Environmental Quality (DEQ) has issued a boil water order;
(b) fecal coliform or E. coli is detected in a nonpublic water supply sample;
(c) the total nitrate level is over 10 mg/L in a nonpublic water supply sample;
(d) a nonpublic water supply sample exceeds a maximum contaminant level as specified in ARM Title 17, chapter 38, subchapter 2;
(e) a pathogenic microorganism is detected; or
(f) a confirmed disease outbreak is associated with the water source by investigation.
(2) An establishment that is subject to a restricted-use order must provide and use a temporary source of potable water as described in (3) for guest and staff drinking, food and drink preparation and service, ice, dishwashing, food contact surface cleaning, and hand washing, or discontinue operations.
(3) With approval from the local regulatory authority, an establishment may provide potable water on a temporary basis using one or more of the following:
(a) bottled or packaged potable water from a department-licensed water bottler, or other approved water bottler, if the water is dispensed directly from the original container;
(b) water from a DEQ-approved public water supply that meets the requirements of ARM Title 17, chapter 38, subchapters 1, 2, 3, and 5, stored in a clean, sanitized, and covered potable water container or holding tank;
(c) water delivered by a department-licensed potable water hauler;
(d) if the water is fecal or E. coli contaminated, water that has been boiled for at least one minute and stored and served from a clean, sanitized, and covered container; or
(e) other source approved by the local regulatory authority.
(4) If the local regulatory authority determines that boiling water will not provide adequate potable water, it may require an establishment to use another approved method for supplying water.
(5) An establishment subject to a restricted-use order must notify guests and staff of the restricted-use order by placing a sign at each point of use, or as otherwise directed by the local regulatory authority.
(6) A water supply under a restricted-use order may not be used to make ice.
(7) An establishment subject to a restricted-use order may wash, rinse, and sanitize dishes, utensils, and equipment using the affected water system if using an approved chemical disinfectant or a commercial dish machine that reaches 180°F (82°C) in the final rinse, or as directed by the local regulatory authority.
(8) A restricted-use order may be removed by the local regulatory authority after:
(a) laboratory sampling demonstrates that the water supply is safe;
(b) the establishment flushes all pipes, faucets, and drinking fountains by running cold water for at least five minutes; and
(c) the establishment flushes, cleans, and sanitizes food and beverage equipment connected to the water supply, such as post-mix beverage machines, spray misters, coffee makers, tea urns, ice machines, glass washers, and dishwashers in accordance with manufacturer's instructions.