Rent Stabilization in Mercer Island, Washington

Last updated: January 2026

Washington's statewide rent increase cap (HB 1217) protects tenants in Mercer Island with rent increase limits and notice requirements.

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1. Overview of Rent Stabilization in Mercer Island

In the greater Seattle area, Mercer Island residents are protected by HB 1217's comprehensive rent stabilization. Washington's Statewide Rent Increase Cap (HB 1217), effective since 2025, provides:

• Rent increase caps – Annual increases limited to 7% + CPI (max 10%)
• 12-month waiting period – No rent increases during the first year of tenancy
• Notice requirements – 90 days written notice required before rent increases

This article provides an overview of how Washington's rent increase cap applies in Mercer Island. It is not legal advice. For specific questions, consult with a qualified attorney or tenant counseling organization.

2. Who Is Covered in Mercer Island?

In Mercer Island, the rent increase cap applies to virtually all residential rental properties, regardless of when they were built. This means tenants in both older and newer buildings benefit from the same protections after their first year of tenancy.

Key Points:

• No construction year cutoff – Unlike some states, Washington applies the cap to properties of all ages
• 12-month waiting period – Rent increases are not permitted during the first 12 months of tenancy
• Property types – Apartments, houses, condos, and other residential rentals are covered

Exemptions:

• Properties exempt from RCW 59.18
• Week-to-week tenancies (may be exempt)

3. Maximum Allowable Rent Increases

For 2026, the maximum allowable rent increase in Mercer Island is **9.683%** (7% + CPI, maximum 10%). This cap is determined annually by the Department of Commerce using Seattle-area inflation data.

2026 Rent Increase Cap:

• Maximum increase: 9.683% (7% + CPI, capped at 10%)

Important Rules:

• Only one rent increase per 12-month period is allowed
• Landlords must provide at least 90 days written notice before any increase
• The cap applies to tenants who have lived in the unit for at least 12 months
• First-year tenants may see increases above the cap (but still need 90-day notice)

4. Notice Requirements for Rent Increases

Tenants in Mercer Island must receive **90 days written notice** before rent can be increased.

Notice Requirements:

• Statewide: 90 days written notice required
• Frequency: Once per 12-month period
• The notice must include the amount of the increase, new rent amount, and effective date

5. 12-Month Waiting Period

HB 1217 establishes a **12-month waiting period** before rent increases can take effect. This means new tenants in Mercer Island are guaranteed stable rent for their first year.

How It Works:

• During your first 12 months, landlords cannot increase rent
• After 12 months, rent increases are subject to the annual cap
• This protection applies to all covered properties, regardless of age

6. Resources for Mercer Island Tenants

If you're a tenant in Mercer Island and have questions about your rights, consider these resources:

• Washington State Department of Commerce - HB 1217 – Official state information about rent increase caps
• Tenants Union of Washington State – Statewide tenant rights organization
• Washington Law Help – Free legal information and resources

You can also use RentCheckMe to check if your building is likely covered based on property information.

7. Important Disclaimer

This article is a high-level overview of Washington's Rent Increase Cap (HB 1217) as it applies in Mercer Island. It does not cover every exception and does not constitute legal advice.

Laws may change, and how they apply depends on your specific situation. For binding guidance, consult with a qualified attorney, the Tenants Union of Washington State, or Washington Law Help.

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