What the rules require of a landlord in unincorporated King County, drawn straight from the rule records this site computes with. Every line links to the source it came from.
This is an informational tool, not legal advice, and we are not your lawyer. Double-check deadlines with a licensed Washington attorney before acting on them.
Local rules go further here
Unincorporated King County requires 120 days' notice for increases over 3% (KCC 12.25.070, Ordinance 19311, with no 180-day tier), caps move-in fees and deposits at one month's rent, and caps late fees at 1.5% of monthly rent. Despite common claims, there is NO rent-increase relocation-assistance program in unincorporated King County.
Unincorporated King County requires at least 90 days of written notice before a rent increase takes effect.
An increase above 3% requires 120 days instead.
Tenancies subsidized through the unit itself get a shorter period of 30 days. A tenant's portable voucher does not count.
Checked against the source on July 26, 2026.
Unincorporated King County caps total move-in charges (security deposit and nonrefundable fees) at 1 month's rent.
Installment rights: 6 equal monthly installments for rental agreements of 6 months or more; 2 equal installments over the first 2 months for shorter or month-to-month agreements.
Subsidized tenancies are exempt from the cap.
Checked against the source on July 26, 2026.
Unincorporated King County caps a residential late fee at 1.5% of the monthly rent.
Checked against the source on July 26, 2026.
Where a local rule is stricter, the local one governs. These apply wherever the property is.
The statewide cap on a rent increase is 9.683% for 2026. The cap that governs an increase is the one in force on its effective date.
No increase at all is allowed during a tenant's first 12 months.
Checked against the source on July 26, 2026.
You have 30 days after the tenancy ends and the tenant moves out to deliver a full and specific written statement and refund the rest of the deposit.
Personal delivery or first-class mail to the tenant's last known address both count.
Checked against the source on July 26, 2026.
Washington requires 90 days of written notice before a rent increase takes effect, whatever the size of the increase.
Tenancies subsidized through the unit itself get a shorter period of 30 days. A tenant's portable voucher does not count.
The increase has to start at the beginning of a rental period.
Checked against the source on July 26, 2026.
This page says what the rules require. The free calculators apply them to one increase, and an account tracks every unit you own and emails you before each deadline.
