Cal. Pub. Util. Code § 90484

The district may construct and operate or acquire and operate works and facilities in, under, upon, over, across, or along any street or public highway or any stream, bay or watercourse, or over any of the lands which are the property of the state, to the same extent that such rights and privilege appertaining thereto are granted to municipalities within the state. The district shall not use any street or public highway in a manner to unnecessarily impair its usefulness.