The State of Washington today became the first US state to impose a net neutrality law that replaces the nationwide regulations repealed by the Federal Communications Commission.

Washington's legislature and governor approved the new law three months ago and arranged for it to take effect as soon as the FCC finalized its repeal. The FCC repeal was finalized today, so Washington's state law has gone into effect.

The Washington state law prohibits home and mobile Internet providers from blocking or throttling lawful Internet traffic and from charging online services for prioritization. The rules will be enforced by the state attorney general under Washington's Consumer Protection Act.

Bill author Drew Hansen, a Democratic state representative from Bainbridge Island, previously told Ars that he expects the state law to be upheld in court. The FCC is trying to preempt state net neutrality laws, but "the FCC doesn't have preemption authority just because it says so," Hansen said.

The law was opposed by the cable and mobile broadband industries, and ISPs or their lobby groups could sue in an attempt to block it. When contacted by Ars today, Rep. Hansen said he's not aware of any lawsuits being filed yet.

More state laws coming up

Oregon also passed a net neutrality law, but it applies only to ISPs that sell Internet service to state or local government agencies, and it doesn't take effect until January 1, 2019.

The governors of five states—Vermont, Hawaii, Montana, New Jersey, and New York—have also issued executive orders to impose net neutrality rules on ISPs that provide Internet service to state government agencies. As a Motherboard story noted, Washington is the first state with a net neutrality law applying broadly to all ISPs.

Washington's law might not end up being the strictest state net neutrality regime, though. The California Senate last month approved stricter net neutrality rules, including a ban on paid data-cap exemptions, and there is pending net neutrality legislation in most states. The California bill still needs approval from the Democratic-majority State Assembly and Governor Jerry Brown.

Separately, more than 20 Democratic state attorneys general have sued the FCC in an attempt to reverse the federal repeal.