California Code, Civil Code - CIV § 8448

(1) Each unit is deemed a separate work of improvement, and completion of each unit is determined separately for purposes of the time for recording a claim of lien on that unit.  This paragraph does not affect any lien right under Section 8402 or 8446.

(2) Material provided for the work of improvement is deemed to be provided for use or consumption in each separate residential unit in which the material is actually used or consumed;  but if the claimant is unable to segregate the amounts used or consumed in separate residential units, the claimant has the right to all the benefits of Section 8446.