The correct rent-increase notice period in Washington depends on which side of a city limit your property sits on, and often on how big the increase is. Pick your city, enter the increase, and this tool answers with the governing period and why.
Washington's baseline is 90 days of written notice for any rent increase. Seattle and, since January 2026, Tacoma require 180 days for an increase of any amount. And a ring of King County cities uses tiered ordinances: a modest increase follows the state baseline, but crossing a threshold (often 3% or 5%) escalates the requirement to 120 or 180 days.
The strictest rule that applies to your property governs. Serving a 90-day notice where the city demands 120 can void the increase and, in some cities, expose you to penalties or relocation assistance.
City. The governing ordinance is decided by where the property sits, not where you live.
Current and planned housing cost. Tiered city rules key off the percentage increase, so both numbers matter. Include recurring fees like parking or storage.
Target effective date. We count backward from it to the last lawful service date, plus the earlier mail-by date.
Tenancy start date. State law bars increases during the tenant's first 12 months; we check that too.
GiveProperNotice turns these one-off checks into a maintained deadline calendar for every unit, with reminders before each date.
Already know your notice period? The notice deadline calculator maps your whole deadline calendar, and the rent cap calculator checks the increase amount itself.
