CA Civ Code Section 8206

(a)

Except as provided in subdivision (b), a claimant need give only one preliminary notice to each person to which notice must be given under this chapter with respect to all work provided by the claimant for a work of improvement.

(b)

If a claimant provides work pursuant to contracts with more than one subcontractor, the claimant shall give a separate preliminary notice with respect to work provided pursuant to each contract.

(c)

A preliminary notice that contains a general description of work provided by the claimant through the date of the notice also covers work provided by the claimant after the date of the notice whether or not they are within the scope of the general description contained in the notice.