Under the laws of Washington State, a prenuptial agreement can be legally enforced, as can co-habitation agreements. However, they must conform to certain principles. The parties to a prenup must understand what the agreement covers. They should each have independent counsel who can advise them, and if necessary, renegotiate clauses in the agreement. The parties to the agreement must also have adequate time to review the agreement.

We generally think of a prenuptial agreement as covering the disposition of property in a divorce. But it can also include provisions for spousal support (alimony) or prohibit spousal support in case of divorce. The terms of such agreements should reflect the wishes and desires of the parties.