Cal. Health and Safety Code § 17922.7

(a) Except as otherwise provided in subdivisions (b) and (c), the governing body of every city, county, city and county, and public entity shall adopt ordinances or regulations imposing the same requirements as are published in the State Building Standards Code relating to noise insulation and as are contained in the other rules and regulations adopted pursuant to Section 17922.6 within six months after the date of publication in the State Building Standards Code or the date of adoption of such other rules and regulations. The building standards relating to noise insulation published in the State Building Standards Code and the other rules and regulations adopted pursuant to Section 17922.6 shall apply in any city, county, city and county, or to any hotel, motel, apartment house, or dwelling other than a detached single-family dwelling, which is owned, operated, or maintained by any public entity, if the appropriate governing body fails to adopt such ordinances or regulations within six months after such date of publication or adoption. (b) In adopting such ordinances or regulations, the governing body of any city, county, city and county, or public entity may make such changes, modifications, or additions to the minimum requirements contained in such building standards relating to noise insulation published in the State Building Standards Code, or in the other rules and regulations adopted pursuant to Section 17922.6, as such governing body determines are reasonably necessary due to local conditions. The governing body may also impose noise insulation standards on a case by case basis on new single-family detached dwellings, if the governing body determines that such standards are necessary due to substantial noise generated by airports, roadways, or commercial and industrial activities immediately surrounding or adjacent to such proposed dwellings. Any local noise insulation standards adopted for single-family detached dwellings shall not exceed comparable standards for multifamily housing. The governing body shall find that ordinances or regulations, adopted pursuant to this subdivision, will require the dimunition of the noise levels permitted by the building standards relating to noise insulation published in the State Building Standards Code and in the other rules and regulations adopted pursuant to Section 17922.6. (c) Prior to making such modifications, changes, or additions pursuant to subdivision (b), the governing body shall make an express finding that such modifications, changes, or additions are needed, which finding shall be available as a public record. A copy of such finding, together with the modification, change, or addition, shall be filed with the Office of Noise Control.