TL;DR
One number shapes Washington’s 2026 rental market: 9.683%. That is the statewide cap on rent increases under House Bill 1217, known as HB 1217. Go over it by even a fraction and the Attorney General’s office can bring civil penalties.
Here is the short version every Seattle-area property manager needs before the next lease renewal.
For 2026, HB 1217 caps rent increases in Washington at 9.683%: 7% plus a CPI of about 2.683%. Give at least 90 days’ written notice, or 180 days in Seattle. Go over the cap and you face civil penalties. Serve the wrong notice period and the increase cannot be enforced.
The Cap: How It's Calculated
HB 1217 sets the most you can raise rent at 7% plus the annual CPI (the Consumer Price Index). For 2026, CPI came in at about 2.683%. That puts the cap at 9.683%.
To check a new rent, multiply the current rent by 1.09683. The answer is the highest new rent you can set. A round 10% increase is already over the line.
Seattle's Extra Rule: 180 Days
Statewide, a Washington rent increase notice must be in writing and given 90 days ahead (RCW 59.18.140). In subsidized housing it is 30 days. Seattle requires 180 days (SMC 7.24.030).
In Seattle, serve notice on June 1 and the increase does not start until late November. Miss the window and you lose the increase for that whole lease term.
What Non-Compliance Looks Like
- Going over the 9.683% cap: civil penalties from the Attorney General
- Wrong notice period: the increase cannot be enforced
- No tenant rights language in the notice: the notice is not valid
The Compliant Notice: 6 Required Elements
Every notice needs these six parts:
- Current rent (exact dollar amount)
- New rent (exact dollar amount)
- Effective date (at least 90 days out, 180 in Seattle)
- The increase in dollars and as a percentage
- Tenant rights language (the right to contact the AG or legal aid)
- Your signature as landlord, with the date
Give the notice in writing, at least 90 days ahead. Keep a record of everything. CPI resets each year, so check the new figure each October when you plan for 2027.
Property Management MarketingMarketing for management companies: owner leads, renter search and website rebuilds.Questions property managers ask about HB 1217
When did HB 1217 take effect in Washington State?
HB 1217 took effect on May 7, 2025. It amended RCW 59.18.140, the state law on rent increase notices, and set the cap at 7% plus annual CPI. For 2026, that formula gives the 9.683% cap. The 90-day notice rule in this post comes from that amended law.
Does the Washington rent cap apply in Seattle?
Yes. The 9.683% cap is statewide, so Seattle landlords are held to it like landlords anywhere else in Washington. Seattle adds its own rule on top: 180 days’ notice for any increase in housing costs, under SMC 7.24.030. So a Seattle increase must stay under the cap and give the longer notice.
Is there a different notice rule for leases signed before HB 1217?
Yes, for some fixed-term leases. A transition rule of 60 days applies to fixed-term leases signed before May 7, 2025 that had 60 to 90 days left. Every other lease follows the notice periods above. Check when the lease was signed and how many days are left on it before you send notice.
Is your property management brand publishing content like this? Kihan Marketing builds SEO and content systems for property management companies. Let’s talk.
Related reading
