Gov. Jay Inslee, a Democrat, signed the measure Wednesday, which puts his state in line with California and Oregon as having some of the nation’s strongest sanctuary policies, The Associated Press reported.
"Our state agencies are not immigration enforcement agencies," said Inslee, who also is running for president. "We will not be complicit in the Trump administration's depraved efforts to break up hard-working immigrant and refugee families."
Under the new rules, police officers will not be able to ask about someone’s immigration status except in limited circumstances. State Attorney General Bob Ferguson will be tasked with drawing up rules for courthouses, hospitals and government-run facilities where federal immigration officials look for illegal immigrants.
Republican state Sen. Phil Fortunato said the law impedes police efforts to deal with people living in the country illegally.
"This not only puts law enforcement at risk, it puts private citizens at risk," he said.
Most police interactions involve city and county law enforcement authorities, said Lena Graber, an attorney with the San Francisco-based Immigrant Legal Resource Center. Wednesday's bill signing expands Inslee's 2017 executive order that imposed similar provisions on state agencies, which immigration advocates argued didn't go far enough.
Graber said the bill would give Washington "the strongest and most comprehensive state law on sanctuary in the country."
Five other states -- Connecticut, Illinois, New Jersey, Rhode Island and Vermont -- have similar policies against cooperation between local and federal law enforcement for non-criminal immigration investigations.
Oregon adopted the nation's first statewide sanctuary policy in 1987. The policy has forbidden police from expending any resources to go after anyone living in the country illegally if they haven't committed any crimes beyond that.
In 2017, California approved a measure requiring authorities to obtain written permission from people they arrest to allow them to be interviewed by immigration officers.
The bill’s co-sponsor, state Sen. Lisa Wellman, voiced concerns for sectors that have relied primarily on immigrant labor, such as agriculture hospitality and technology.
"We have 30 percent of Microsoft here on visas," Wellman, a Democrat, said before a public hearing for the bill in the state Legislature earlier this year. "You can't open a hotel if you don't have immigrants in back-of-house."
The Associated Press contributed to this report.