California Code
CHAPTER 2 - Joint or Several Obligations
Section 1431.

1431. Joint Liability

An obligation imposed upon several persons, or a right created in favor of several persons, is presumed to be joint, and not several, except as provided in Section 1431.2, and except in the special cases mentioned in the title on the interpretation of contracts. This presumption, in the case of a right, can be overcome only by express words to the contrary.

(Amended June 3, 1986, by initiative Proposition 51, Sec. 2. Note: Prop. 51 (the Fair Responsibility Act of 1986) includes Sections 1431.1 to 1431.5 and part of this section.)