Gregoire and Secretary of State Sam Reed certified the election on Wednesday afternoon, as they were joined by couples who plan to wed. The law doesn't take effect until Thursday, when gay and lesbian couples can start picking up their wedding certificates and licenses at county auditors' offices. King County, the state's largest and home to Seattle, and Thurston County, home to the state capital of Olympia, will open the earliest, at 12:01 a.m. Thursday, to issue marriage licenses.
Because the state has a three-day waiting period, the earliest that weddings can take place is Sunday. Same-sex couples who previously were married in another state that allows gay marriage, like Massachusetts, will not have to get remarried in Washington state. Their marriages will be valid here as soon as the law takes effect.
"This is a very important and historic day in the great state of Washington," Gregoire said before signing the measure that officially certified the election results. "For many years now we've said one more step, one more step. And this is our last step for marriage equality in the state of Washington."
Last month, Washington, Maine and Maryland became the first states to pass same-sex marriage by popular vote. They joined six other states - New York, Connecticut, Iowa, Massachusetts, New Hampshire, Vermont - and the District of Columbia that had already enacted laws or issued court rulings permitting same-sex marriage.
Referendum 74 in Washington state had asked voters to either approve or reject the state law legalizing same-sex marriage that legislators passed earlier this year. That law was signed by Gregoire in February but was put on hold pending the outcome of the election. Nearly 54 percent of voters approved the measure.
The law doesn't require religious organizations or churches to perform marriages, and it doesn't subject churches to penalties if they don't marry gay or lesbian couples.
Maryland's law officially takes effect Jan. 1, however couples can start picking up marriage licenses on Thursday, as long as the license has an effective date of Jan. 1. Whether clerks of court issue a postdated license is up to them, however. They are not required to do so. Maine's law takes effect on Dec. 29. There's no waiting period in Maine, and people can start marrying just after midnight.
In addition to private ceremonies that will start taking place across Washington state this weekend, Seattle City Hall will open for several hours on Sunday, and several local judges are donating their time to marry couples. Aaron Pickus, a spokesman for Mayor Mike McGinn, said that more than 140 couples have registered to get married at City Hall, and weddings will begin at 10 a.m.
Washington state has had a domestic partnership law in place since 2007. The initial law granted couples about two dozen rights, including hospital visitation and inheritance rights when there is no will. It was expanded a year later, and then again in 2009, when lawmakers completed the package with the so-called "everything but marriage" law that was ultimately upheld by voters later that year.
This year, lawmakers passed the law allowing gay marriage, and Gregoire signed it in February. Opponents gathered enough signatures for a referendum, putting the law on hold before it could take effect.
There are nearly 10,000 domestic partnership registrations with the secretary of state's office. Most same-sex domestic partnerships that aren't ended prior to June 30, 2014, automatically become marriages, unless one of the partners is 62 or older.
That provision was included in the state's first domestic partnership law of 2007 to help heterosexual seniors who don't remarry out of fear they could lose certain pension or Social Security benefits.