Pub. Util. Code, § 17010

Whenever, in the opinion of the board, the public interest or convenience may require, it may order to be done in, under, or upon the whole or any portion of any one or more of the streets or public places of the district, or any property or rights-of-way owned by the district, any work or improvement which the district is authorized to do and provide that the cost thereof shall be assessed upon the lots and lands fronting on the streets or public places, or upon any district which may be assessed therefor, and which need not be composed of lands contiguous to each other. The Improvement Act of 1911, the Municipal Improvement Act of 1913, and the Improvement Bond Act of 1915, as now or hereafter provided, are applicable to districts.