Code of Civil Procedure § 1203.63
CHAPTER 2.5. Oil and Gas Liens
The taking of any note or any additional security by any person given a lien by this chapter shall not constitute a waiver of the lien given by this chapter unless made a waiver by express agreement of the parties in writing. The claiming of a lien under this chapter shall not constitute a waiver of any other right or security held by the claimant unless made a waiver by express agreement of the parties in writing.