California Code, Civil Code - CIV § 8319

(1) The design professional lien expires pursuant to paragraph (1) of subdivision (b) of Section 8306.

(2) The design professional lien remains fully or partially unpaid.

(3) Within 30 days of the expiration of the design professional lien pursuant to paragraph (1) of subdivision (b) of Section 8306, the design professional records a mechanics lien for the amount of the unpaid design professional lien.

(4) The recorded mechanics lien states that it is a converted design professional lien but shall be recorded and enforced as a mechanics lien, except the design professional need not provide a preliminary notice to enforce this mechanics lien.  This mechanics lien shall be effective as of the date of recordation of this mechanics lien and shall be given priority pursuant to the provisions of Section 8450.