California Code, Government Code - GOV § 50078.5

(a) The legislative body may establish zones or areas of benefit within the local agency and may restrict the imposition of assessments to areas lying within one or more of the zones or areas of benefit established within the local agency.

(b) The benefit assessment shall be levied on a parcel, class of improvement to property, or use of property basis, or a combination thereof, within the boundaries of the local agency, zone, or area of benefit.

The assessment may be levied against any parcel, improvement, or use of property to which such services may be made available whether or not the service is actually used.