2009 California Government Code - Section 39501-39502 :: Article 1. General

39501.  The legislative body may compel the owner, lessee, or
occupant of buildings, grounds, or lots to remove dirt, rubbish,
weeds, and rank growths from buildings or grounds and adjacent
sidewalks. If he defaults, after notice prescribed by the legislative
body, it may authorize the removal or destruction of the dirt,
rubbish, weeds, and rank growths at his expense by a city officer.
The legislative body may prescribe a procedure for the removal or
destruction and make the expense a lien upon the buildings or
grounds.

39502.  By ordinance the legislative body may:
   (a) Require and provide for the removal of grass, weeds, or other
obstructions from the sidewalks, parkings, or streets and make the
cost of removal a lien upon the abutting property.
   (b) Require or provide for the removal from property, lands, or
lots of all weeds, rubbish, or other material dangerous or injurious
to neighboring property or the health or welfare of residents of the
vicinity and make the cost of removal a lien upon the property.
   (c) Provide for the enforcement of the lien by the sale of the
property or otherwise.