Cal. Harbors and Navigation Code § 654.05

(a) The owner of a motorized recreational vessel that is numbered pursuant to Section 9850 of the Vehicle Code, or that is documented by an agency of the federal government, shall not operate, or authorize the operation of, the vessel in or upon the inland waters, or in or upon ocean waters that are within one mile of the coastline of the state, in a manner that exceeds the following noise levels: (1) For engines manufactured before January 1, 1993, a noise level of 90 dB(A) when subjected to the Society of Automotive Engineers Recommended Practice SAE J2005 (Stationary Sound Level Measurement Procedure for Pleasure Motorboats). (2) For engines manufactured on or after January 1, 1993, a noise level of 88 dB(A) when subjected to the Society of Automotive Engineers Recommended Practice SAE J2005 (Stationary Sound Level Measurement Procedure for Pleasure Motorboats). (3) A noise level of 75 dB(A) measured as specified in the Society of Automotive Engineers Recommended Practice SAE J1970 (Shoreline Sound Level Measurement Procedure). However, a measurement of noise level that is in compliance with this paragraph does not preclude the conducting of a test of noise levels under paragraph (1) or (2). (b) A law enforcement officer utilizing a decibel measuring device for the purposes of enforcing this section shall be knowledgeable and proficient in the use of that device. (c) The department may, by regulation, revise the measurement procedure when deemed necessary to adjust to advances in technology. (d) This section does not apply to motorized recreational vessels competing under a local public entity or United States Coast Guard permit in a regatta, in a boat race, while on trial runs, or while on official trials for speed records during the time and in the designated area authorized by the permit. In addition, this section does not apply to motorized recreational vessels preparing for a race or regatta if authorized by a permit issued by the local entity having jurisdiction over the area where these preparations occur. (e) This section shall become operative on January 1, 2005.