California Code, Civil Code - CIV § 1525

It is the public policy of this State, in the best interests of the taxpayer and of the litigant, to encourage fair dealing and to promote justice by reducing litigated matters to the lowest level of jurisdiction.

In case of a dispute over total money due on a contract and it is conceded by the parties that part of the money is due, the debtor may pay, without condition, the amount conceded to be due, leaving to the other party all remedies to which he might otherwise be entitled as to any balance claimed.

If any conditions are attached to the payment, this section shall not be deemed to have limited the remedies available to the other party under other provisions of law on the original amount claimed.