Key Takeaways
- The 7% cap is mandatory statewide — RCW 59.18.140 limits annual rent increases to the lesser of 7% or the prior year’s Consumer Price Index (CPI) plus 1 percentage point, effective for all leases renewed or entered into after January 1, 2025.
- Violations carry significant penalties — Charging rent above the legal limit constitutes an unfair practice under the Consumer Protection Act (RCW 19.86), exposing landlords to treble damages, attorney fees, and civil penalties up to $2,000 per violation.
- Limited exemptions exist — New construction (less than 5 years old), nonresidential property, subsidized housing, and owner-occupied duplexes are exempt, but the burden of proof is on the landlord.
- The CPI formula changes annually — The allowed increase resets each calendar year on January 1st, calculated from the most recent annual CPI data published by the U.S. Bureau of Labor Statistics (Seattle-Tacoma-Bellevue, all urban consumers).
- Written notice is required — Any rent increase at or below the legal cap must still comply with notice requirements (30, 60, or 90 days depending on tenancy length) and must be provided in writing before the increase takes effect.
- Documentation is critical — Self-managing landlords must maintain records of CPI calculations, lease renewal dates, and rent increase notices to defend against tenant complaints filed with the Attorney General’s Office.
What Is HB 1217 and When Does It Apply?
Effective January 1, 2025, Washington’s HB 1217 (codified in RCW 59.18.140) imposed the state’s first statewide rent control measure. This law directly affects your ability to raise rent and requires precise calculation and documentation.
The core rule: You cannot increase rent by more than the lesser of (1) 7% or (2) the previous year’s Consumer Price Index (CPI) for the Seattle-Tacoma-Bellevue region plus 1 percentage point.
This applies to:
- Month-to-month tenancies
- Lease renewals (when the lease term ends)
- New leases for occupied units (if the prior tenant paid a lower rent)
- All residential rental properties with one or more units
The law does NOT grandfather existing leases. If you have a tenant on a fixed lease that ends in 2026 or later, the increase on renewal is subject to the 7% cap, regardless of what their original lease said.
Understanding the CPI Formula: How to Calculate Your Legal Rent Increase
The mathematics of HB 1217 matter. Miscalculating even by 1% can expose you to liability. Here’s the exact formula:
Allowed Rent Increase = Lesser of:
- 7%, OR
- (CPI for the preceding 12-month period) + 1%
The CPI component: Washington uses the Consumer Price Index for All Urban Consumers (CPI-U) for the Seattle-Tacoma-Bellevue metropolitan statistical area, published by the U.S. Bureau of Labor Statistics. This is not your choice—it’s the statutory benchmark. Data is released monthly, and the annual percentage is calculated from the most recent 12-month period.
For 2026, the applicable CPI calculation is based on the 12-month change ending December 2025. As of August 2026, you should already know the exact percentage for any rent increase effective in the latter half of 2026.
Practical example:
- CPI for 12 months ending December 2025 = 3.2%
- CPI + 1% = 3.2% + 1% = 4.2%
- Allowed increase = Lesser of 7% or 4.2% = 4.2%
- If tenant’s current rent is $2,000/month, new maximum rent = $2,000 × 1.042 = $2,084/month
The cap resets on January 1 each calendar year. Even if you didn’t raise rent in 2025, you cannot compound increases. The 7% (or CPI+1%) limit applies to each 12-month period independently.
Where to Find the Official CPI Data
Do not rely on news reports or estimates. The U.S. Bureau of Labor Statistics publishes official data at bls.gov/regions/pacific/home.htm. Look for the Seattle-Tacoma-Bellevue series number APUU49557SA0 (All items index for all urban consumers). This data is released on the second-to-last business day of each month.
For maximum compliance confidence, obtain the CPI data from the official source, print it, and retain it with your lease records. If a tenant or attorney challenges your calculation, you’ll have documented proof that your math was correct.
Who Is Exempt From the Rent Cap?
RCW 59.18.140 includes four narrow exemptions. If your property qualifies, you may be able to raise rent above the cap—but you must prove it.
Exemption 1: New Construction (Less Than 5 Years Old)
Buildings first occupied after January 1, 2020 are exempt from the rent cap for 5 years from the date of first occupancy. After that 5-year period ends, the cap applies.
What counts as “first occupancy”? The date a unit is ready for and first rented to a tenant. If you completed a new building in June 2023, all units remain exempt through June 2028, then the cap kicks in on July 1, 2028.
Burden of proof: You must be able to document the construction completion date and first lease commencement date. Keep your Certificate of Occupancy and initial lease on file.
Exemption 2: Nonresidential Property
Commercial, office, retail, industrial, and agricultural uses are not covered by RCW 59.18.140. The rent cap applies only to residential tenancies. If you rent a ground-floor retail space to a business, HB 1217 does not apply.
What about mixed-use? A unit that is genuinely used for both residential and commercial purposes (rare) may fall outside the law, but the default is to assume residential units are covered. Consult an attorney if you have a genuinely mixed-use unit.
Exemption 3: Subsidized Housing
Housing where the rent is subsidized by a federal, state, or local housing assistance program is exempt. Examples include Section 8 voucher units, public housing authority properties, and some low-income housing tax credit properties.
Key point: The exemption applies because the subsidy program controls the rent, not you. If a tenant has a Section 8 voucher, the Housing Authority and the lease agreement (not HB 1217) determine the rent split between tenant and subsidy.
Exemption 4: Owner-Occupied Duplexes
If you own a duplex, live in one unit, and rent out the other, the rental unit is exempt from the rent cap. This exemption assumes direct owner involvement and limited portfolio size.
Critical requirement: You must live in one of the two units as your primary residence. If you own a duplex, live elsewhere, and rent both units, the exemption does not apply.
The burden of proof is on you. If a tenant disputes your exemption claim, you will need to prove your primary residence status (utility bills, voter registration, etc.). Keep this documentation accessible.
When and How to Provide Notice of a Rent Increase
Even if your increase is legal under the 7% cap, Washington law requires proper notice. RCW 59.18.200 specifies notice periods based on tenancy length:
| Tenancy Length | Notice Period Required | Examples |
|---|---|---|
| Less than 1 year | 30 days | Month-to-month tenants, tenants in first year |
| 1 year or more, less than 2 years | 60 days | Tenants in second year of occupancy |
| 2 years or more | 90 days | Long-term tenants, 2+ year occupancy |
Counting the notice period: Notice must be provided in writing at least the specified number of days before the effective date of the increase. If you provide written notice on January 15, a 30-day notice takes effect February 14 (not February 15). Courts count the date of notice as day zero.
What must the notice contain? Washington does not specify a statutory form, but your notice should include:
- Current rent amount
- New rent amount
- Effective date of increase
- Statement that the increase complies with RCW 59.18.140 (optional but protective)
- Calculation of the percentage increase (optional but protective)
Best practice: Retain a signed or stamped copy of the notice, the method of delivery, and the date delivered. If a dispute arises, you’ll have evidence of compliance with notice requirements.
Common Compliance Mistakes Self-Managing Landlords Make
Mistake 1: Using the Wrong CPI Series
Washington law specifies the Seattle-Tacoma-Bellevue CPI. Some landlords mistakenly use the national CPI-U, the West region CPI, or older data. This leads to overstated rent increases and exposure to liability.
Fix: Bookmark the official BLS page and pull the Seattle-Tacoma-Bellevue data directly each January. Do not estimate or use regional approximations.
Mistake 2: Compounding Increases Year-Over-Year
Some landlords incorrectly believe that if they raised rent 3% in 2025, they can raise it another 4.2% in 2026. Each calendar year resets. The 7% cap applies to the increase from the current rent to the new rent, not to a “carryover” from prior years.
Fix: Calculate each increase independently from the rent in effect on the date the increase takes effect.
Mistake 3: Failing to Document Exemptions
Exemptions are affirmative defenses. If you claim new construction or owner-occupancy and a tenant challenges it, you cannot rely on memory. You need dated, contemporaneous documents.
Fix: Create a property file that includes construction/occupancy dates, Certificate of Occupancy, primary residence documentation, or subsidy agreements. Update it annually.
Mistake 4: Providing Oral Notice Instead of Written
Washington law requires written notice of rent increases. Text messages, emails, and verbal announcements are not sufficient in a legal dispute.
Fix: Always send written notice via certified mail, email with read receipt, or hand delivery with signature. Retain proof of delivery.
Mistake 5: Not Calculating the Increase Percentage Correctly
A rent increase from $2,000 to $2,150 is 7.5% ($150 ÷ $2,000 = 0.075), which exceeds the 7% cap if CPI+1% is lower. Rounding errors and mental math mistakes are costly.
Fix: Use a calculator. Percentage increase = (New Rent – Old Rent) ÷ Old Rent × 100. Document your calculation and keep it with the notice.
Penalties and Enforcement: What Happens if You Violate HB 1217
Consumer Protection Act Liability
A rent increase above the legal cap is classified as an unfair or deceptive practice under Washington’s Consumer Protection Act (RCW 19.86.140). This is serious.
Penalties include:
- Treble damages: Three times the amount of rent overcharged (e.g., if you charged $300 extra over a year, you owe $900)
- Civil penalty: Up to $2,000 per violation (each excessive increase or month may count as a separate violation)
- Attorney fees and costs: Tenants who pursue claims under RCW 19.86 can recover their lawyer’s fees if they win
Example: You raised rent $400/month in excess of the legal cap for 12 months ($4,800 total overcharge). The tenant sues and wins. You owe $4,800 × 3 = $14,400 in treble damages, plus court costs and potentially $5,000–$15,000 in the tenant’s attorney fees.
Attorney General Enforcement
The Washington Attorney General’s Office has authority to enforce RCW 59.18.140. Tenants can file complaints, and the AG can investigate and pursue civil action on behalf of tenants or in the public interest.
Enforcement actions by the AG are not required for a private tenant lawsuit to proceed. A single tenant’s complaint can trigger AG investigation, resulting in a formal notice of violation and demand for restitution to all affected tenants.
Class Action Risk
If you’ve rented to multiple tenants and violated the cap consistently, you face class action exposure. Attorneys representing tenants will file claims on behalf of all tenants affected in a defined period. Damages multiply quickly in a class setting.
Practical Compliance Checklist for Self-Managing Landlords
Before each rent increase, complete the following:
- Verify exemption status
- ☐ Is the property new construction (less than 5 years from first occupancy)? If yes, retain proof of occupancy date.
- ☐ Is the property nonresidential? If yes, confirm the lease is commercial, not residential.
- ☐ Is rent subsidized by a government program? If yes, retain subsidy agreement or Section 8 authorization.
- ☐ Is this an owner-occupied duplex with me living in one unit? If yes, retain proof of primary residence.
- Determine the applicable cap
- ☐ Pull the official CPI-U data for Seattle-Tacoma-Bellevue from bls.gov for the past 12 months.
- ☐ Calculate: CPI percentage + 1% = X%
- ☐ Determine the cap: Lesser of 7% or X%
- ☐ Document the CPI source and calculation date.
- Calculate the maximum allowable increase
- ☐ Identify current rent (the rent in effect on the date of notice).
- ☐ Multiply by the cap percentage: Current Rent × (1 + Cap%) = Maximum New Rent
- ☐ Determine the proposed new rent (do not exceed maximum).
- ☐ Verify: (New Rent – Current Rent) ÷ Current Rent × 100 = percentage increase (should not exceed cap)
- Determine notice period
- ☐ Count days of tenancy (from move-in date to today).
- ☐ If less than 1 year: 30-day notice required.
- ☐ If 1–2 years: 60-day notice required.
- ☐ If 2 or more years: 90-day notice required.
- Draft and deliver written notice
- ☐ Create written notice in a clear format.
- ☐ Include current rent, new rent, effective date, and calculation details.
- ☐ Deliver via certified mail, email with read receipt, or hand delivery with signature.
- ☐ Count days from delivery to ensure compliance with notice period (day of notice = day 0).
- ☐ Retain proof of delivery (certified mail receipt, email confirmation, signature).
- Document and file
- ☐ Create a property file folder (digital or physical) for each rental unit.
- ☐ Store lease agreement, all rent increase notices, proof of delivery, and CPI documentation.
- ☐ Maintain records for at least 3 years (statute of limitations for consumer protection claims).
Technology Solutions for Rent Cap Compliance
Manual calculation and tracking of rent increases across multiple units and years is error-prone. Many self-managing landlords use spreadsheets, which lack built-in audit trails and validation.
A compliance engine designed for landlords can:
- Auto-populate official CPI-U data for your region each January
- Calculate the 7% vs. CPI+1% cap automatically
- Generate compliant rent increase notices with proper notice periods
- Flag properties that may qualify for exemptions and prompt documentation
- Maintain audit trails of all notices and calculations for defense in disputes
- Alert you when notice deadlines approach for lease renewals
For portfolios of 2–75 units, this level of automation reduces both compliance risk and administrative time. LeaseBase’s platform is built around the principle that self-managing landlords should have the same compliance infrastructure as large property management companies, without the $800+/month management fee.
Frequently Asked Questions
Q: Can I raise rent between lease renewals if the tenant stays month-to-month?
A: Yes, but the same 7% cap and notice requirements apply. You cannot increase rent more often than once per 12 months unless both you and the tenant agree in writing. Even on a month-to-month tenancy, you must provide 30 days’ written notice for the first year, 60 days for year two, and 90 days thereafter. The increase cannot exceed the legal cap for the calendar year in which it takes effect.
Q: What if I didn’t raise rent last year? Can I raise it more this year to catch up?
A: No. The cap applies to each increase independently. You cannot “carry over” unused increase allowance to the next year. If you raised rent 2% in 2025 (below the 7% cap), you can only raise it another 7% (or CPI+1%, whichever is lower) in 2026. The unused 5% from 2025 does not add to your 2026 allowance.
Q: If I live in a duplex and rent the other unit, is my property exempt?
A: Only if the unit you rent is exempt under RCW 59.18.140(2)(d). You must live in one of the two units as your primary residence. If you own the duplex but live elsewhere, the exemption does not apply. Be prepared to prove primary residence status (utility bills, voter registration, mortgage statement) if challenged.
Q: Can I charge a fee instead of raising rent to increase my income?
A: No. Washington law prohibits “junk fees” and secondary charges that effectively circumvent rent control. If a new fee is introduced in conjunction with a rent increase (or instead of one), and the combined effect increases the tenant’s total housing cost, it may violate the intent of HB 1217 and constitute an unfair practice. Stick to rent increases only, within the cap.
Q: What if my CPI calculation differs from the tenant’s? Who is correct?
A: Use the official CPI-U data published by the U.S. Bureau of Labor Statistics for Seattle-Tacoma-Bellevue. If a dispute arises, that official data is the legal benchmark. To avoid disputes, include your CPI source and calculation in the written notice. This demonstrates good faith and protects you in any subsequent legal proceeding.
Q: How long do I need to keep rent increase notices and CPI documentation?
A: Washington’s statute of limitations for consumer protection claims under RCW 19.86 is three years. Keep all rent increase notices, delivery proof, lease agreements, and CPI calculations for at least three years from the date of each increase. If a tenant later claims you overcharged them, you’ll have documentation to prove compliance.
Key Dates and Deadlines for 2026
January 1, 2026: The rent cap for 2026 is calculated based on the CPI for the 12-month period ending December 2025. This rate applies to all rent increases effective from January 1–December 31, 2026.
Ongoing: The U.S. Bureau of Labor Statistics releases updated CPI data on the second-to-last business day of each month. Check bls.gov in December 2025 to determine the exact cap for 2026 rent increases.
Lease renewals: If a tenant’s lease ends in late 2026, the increase on renewal must comply with the 2026 cap (based on CPI for 12 months ending December 2025). Increases for renewals effective January 1, 2027 will use the 2027 cap (based on CPI for 12 months ending December 2026).
Bottom Line: Why Compliance Matters More Than You Think
HB 1217 is not a guideline—it’s a statutory requirement backed by treble damages, attorney fee liability, and AG enforcement. A single miscalculation or improperly delivered notice can expose you to five-figure liability and legal costs that dwarf any rent increase you were trying to collect.
Self-managing landlords in Washington must treat rent cap compliance as a core operational function, not an afterthought. The cost of a mistake—in legal fees, restitution, and court time—justifies investing in tools and processes to get it right the first time.
For portfolios of 2–75 units, lease operations tools that automate rent increase calculations, notice generation, and deadline tracking can be the difference between confident compliance and costly errors.
Disclaimer: This article is for informational purposes only and does not constitute legal advice. Consult a qualified attorney licensed in Washington for guidance specific to your situation, property, or tenant circumstances. Rent control laws are complex and fact-dependent. The information here reflects the law as of August 2026 and may change.