The key requirement is cohabitation while holding themselves out as being married. Mere cohabitation without holding themselves out as a married couple does not constitute marriage.

Common law marriage is recognized only in the following states:

• Alabama
• Colorado
• District of Columbia
• Georgia (if created before 1/1/1997)
• Idaho (if created before 1/1/1996)
• Iowa
• Kansas (both age 18 or older)
• Montana
• New Hampshire (for inheritance purposes only, effective only at death)
• Ohio (if created before 10/10/1991)
• Oklahoma (if created before 11/1/1998)
• Pennsylvania (see below)
• Rhode Island
• South Carolina
• Texas ("informal marriage")
• Utah (only if validated by court/administrative order)

Note that since common law marriage is a state phenomenon, you need to check the laws in the relevant state. There are subtle differences among the states. For example, in some states there is a form you can file to declare an informal marriage.

On September 17, 2003, the Commonwealth Court of Pennsylvania ruled that it would no longer recognize common-law marriages in Pennsylvania in PNC Bank Corp. v. Workers Comp. Bd. (Stamos) (860 CD 2002). It is unclear, however, whether this decision is binding for federal student aid purposes, because it is not necessarily consistent with State law as interpreted by the Pennsylvania Supreme Court. If this decision is upheld on appeal, it does not affect any unions prior to September 17, 2003.

Note that if a couple were living together in a common law marriage, and then moved to a state that doesn't recognize common law marriages, they are still considered married. This is because of the "Full Faith and Credit" clause of the US Constitution (Section 1 of Article IV).

A vacation in a common law state does not normally result in a common law marriage if the couple resides in a state that does not recognize common law marriages.

If the financial aid administrator has any questions as to whether the couple is married, he or she can create a "Documentation of Common Law Marriage Form" that the couple would complete asserting that as of a particular date they agreed to be married, have lived in one of the states listed above as husband and wife after that date, and have represented to others that they are married. The form must be signed by both husband and wife in the presence of a notary and must be notarized. If they complete the form, that's sufficient documentation, since the form itself satisfies the requirements for a common law marriage. Several states already have such a form; in Texas it is called the Declaration and Registration of Informal Marriage form.

The following table summarizes the requirements for a common law marriage in each state.

State	Common Law Marriage Requirements
Alabama	capacity, agreement to be married, consummation
Colorado	cohabitation, reputation as married
District of Columbia	intent, cohabitation
Iowa	intent, agreement, cohabitation, public declarations of husband/wife status
Kansas	capacity, agreement, represent to public as married
Montana	capacity, agreement, cohabitation, reputation as married
Oklahoma	competent, agreement, cohabitation
Pennsylvania	verbal exchange between the couple expressing intent and agreement to be married
Rhode Island	intent, conduct that yields a reputation as married
South Carolina	couple intends for others to believe the couple is married
Texas	sign a form provided by the county clerk, agreement, cohabit, represent to others as married
Utah	capacity, competent, cohabitation, reputation as married

See also the discussion of common law marriage on the National Conference of State Legislatures web site and on the Wikipedia web site.