Senate approves detached-ADU law while rejecting broad water-metering exemptions

The Washington State Senate passed Engrossed House Bill 1345 on March 2, approving a statute that permits detached accessory dwelling units (ADUs) outside urban growth areas while retaining water-metering requirements for those units. The final roll call recorded 33 ayes, 15 nays and 1 excused, and the bill was declared passed.

Lawmakers said the bill aims to expand attainable housing options in rural communities while balancing water-resource protections. "This bill creates opportunities where people can better utilize their property," said Senator Loveland in floor remarks supporting the measure. Senator Bateman, a sponsor and former educator, described constituent stories about families who would benefit and urged colleagues to support increased flexibility in rural housing rules: "If you can have an attached accessory dwelling unit, there's no reason why you shouldn't be able to have a detached," she said.

Much of the debate centered on proposed amendments that would have exempted detached ADUs and rural counties from the bill's water-metering mandate. Senator Wagner argued against such exemptions, calling residential well metering intrusive and costly and saying it would undercut the bill's intent to produce usable housing. Opponents of the exemptions warned that requiring metering could raise construction costs and discourage participation, especially in low-density frontier counties.

Several amendment attempts were considered on the floor. A committee amendment and a proposed change to exempt frontier counties were debated but not adopted; one amendment (number 0762) was formally withdrawn. Senators who opposed the exemptions noted prior court and administrative contexts—citing the Hearst decision and local memoranda addressing water allocations—and said monitoring use helps prevent unintended groundwater impacts.

The Senate recorded multiple roll calls and a division on pivotal amendments before taking final action on the engrossed bill. With passage on final reading, the bill's title was declared the title of the act and the bill will be enrolled as passed.

Implementation details, including any required administrative rules, will follow through the responsible agencies and subsequent rulemaking processes. The Senate moved on to other floor business after the vote.