How to Calculate Your Oregon Rent Increase — Compliance Requirements & CPI Method (2026)

Why Oregon's Rent Increase Formula Matters (and When It Applies)

You can't raise rent to whatever the market allows in Oregon. Under ORS 90.323(2), the state has imposed a statewide rent increase cap that applies to most residential tenancies. This isn't a suggestion—it's a legal ceiling. Exceeding it triggers tenant claims that survive even after the tenant vacates, meaning a former tenant can sue you months or years after moving out.

The law is deceptively simple on its face but demands precision in execution. Most landlords fail not because they don't understand the concept, but because they use the wrong CPI index, calculate from the wrong baseline, or miss the 90-day notice deadline. Each mistake has different consequences.

As of October 2026, many Oregon landlords are already planning 2027 rent increases. The CPI data you'll need is either available now (for leases renewing soon) or will be published by the Bureau of Labor Statistics in the coming weeks. Getting this right requires knowing which index to pull, when to pull it, and what math to apply.

The Statutory Framework: ORS 90.323(2) Explained

Oregon Revised Statutes 90.323(2) establishes the rent increase limit. The law states:

"A landlord shall not increase the rent for a tenancy for an amount greater than the percentage increase in the Consumer Price Index for the West Region, all items, all urban consumers (CPU U) calculated on a 12-month basis as published by the Bureau of Labor Statistics, plus 7 percent."

Break this down into components:

1. The baseline is the CPI-U for the West Region — not the U.S. city average, not the Portland-Salem index, but specifically the West Region all-items index. This is critical. Many landlords accidentally use the national index.
2. The calculation is 12-month basis — you measure the percentage change over the prior 12 months, not a single month or quarterly average.
3. The data source is the Bureau of Labor Statistics — this is the official U.S. government agency that publishes CPI data, available free at bls.gov.
4. You add 7 percent to the CPI increase — if CPI rises 3%, your allowable increase is 10%. If CPI drops 1%, your allowable increase is 6%.
5. The cap applies to most tenancies — but exemptions exist (see below).

Which Buildings Are Subject to the Rent Increase Cap?

The rent increase limit in ORS 90.323(2) applies to nearly all residential tenancies in Oregon with important exceptions. Understanding whether your unit is covered is the first compliance step.

Buildings Subject to the Cap

• Apartment buildings and multi-unit complexes
• Single-family homes rented to tenants
• Condominiums rented to tenants
• Manufactured home parks
• Buildings constructed before January 1, 1990
• Buildings where a prior tenant was subject to rent control (even if you acquired it recently)

Buildings Exempt from the Cap

Under ORS 90.323(3), you are NOT subject to the rent increase cap if:

1. The building was constructed on or after January 1, 1990, AND
2. No prior tenancy in the building was subject to the rent control cap

This exemption is absolute but narrow. If you own a new apartment complex built in 2022 and no tenant has ever lived there, you can raise rent without limitation. However, the moment you rent to a tenant (any tenant), the building becomes subject to the cap for that tenant and all subsequent tenants, permanently. You cannot opt out later.

The statute does not provide for self-certification of exemption. If a tenant disputes whether your building qualifies, you may need to produce construction permits, building records, or lease history to prove your exemption. Many disputes arise when landlords claim exemption without documentation.

Step-by-Step: How to Calculate Your Allowable Rent Increase

Step 1: Identify the Applicable CPI-U West Region Data

The CPI data you use must be the most recent 12-month average available at the time you provide notice. For a notice provided in November 2026, you would use CPI data through September 2026 (the most recent month published by BLS as of the notice date).

The Bureau of Labor Statistics publishes CPI data monthly, typically around the 11th of each month, with a lag of about 1-2 weeks from the end of the measurement month. The data is free and searchable at bls.gov/regions/west/.

The specific series ID you need is CUUR0400SA0 (Consumer Price Index-U for the West Region, all items).

Step 2: Calculate the 12-Month Percentage Change

Once you have the CPI-U West data, calculate the percentage change year-over-year.

Formula:

((Current Month CPI - Prior Year Same Month CPI) / Prior Year Same Month CPI) × 100 = % Change

Example:

• September 2025 CPI-U West: 325.4
• September 2026 CPI-U West: 335.2
• Calculation: ((335.2 - 325.4) / 325.4) × 100 = 2.99%

Step 3: Add 7 Percent to the CPI Increase

Once you have the 12-month CPI percentage increase, add 7 percentage points (not 7% of the CPI increase, but a flat 7 points).

Using the example above:

• CPI increase: 2.99%
• Add 7%: 2.99% + 7% = 9.99% (typically rounded to 10.0%)
• Allowable rent increase: up to 10.0%

If a tenant's current rent is $1,500, the maximum new rent is $1,500 × 1.10 = $1,650.

Step 4: Apply the Increase (or Less)

You can increase rent by any amount up to and including your calculated cap. You do not have to increase by the full allowable amount. Some landlords increase by 5% when the cap is 10%, or by 3% to remain competitive. The law sets the ceiling, not the floor.

The 90-Day Notice Requirement: Timing and Compliance

ORS 90.323(1) requires that you provide at least 90 days' written notice before any rent increase takes effect. This is not a suggestion or best practice—it is a hard statutory requirement. Violations are serious.

What Constitutes Proper Notice?

• Written form — email, certified mail, hand delivery, or posted on the unit door all qualify. Text message does not.
• 90 days before effective date — if you provide notice on October 15, 2026, the earliest effective date is January 13, 2027. Count inclusively (day 1 is the day notice is given or received).
• Specifies the new rent amount — ambiguous notices (e.g., "we will discuss rent next month") do not comply.
• States the effective date clearly — confusion about when the increase starts is the most common defect in notices.

What Happens If You Fail to Provide 90 Days' Notice?

Under ORS 90.323(1), if you do not provide 90 days' notice, the rent increase is void. You cannot collect the increased rent. Additionally:

• The tenant may refuse to pay the increase without being in breach.
• The tenant may sue you for the overcharge amount (the difference between what you collected and what you should have collected).
• The tenant may recover treble damages (three times the overcharge) if the underpayment was willful.
• The tenant may recover attorney fees and court costs — this alone can cost $2,500–$8,000+ in a District Court case.
• The tenant can bring this claim even after moving out, as there is no statute of limitations stated in the statute (claims likely survive under general contract law principles).

Example: You increase rent from $1,500 to $1,800 effective January 1, 2027, but only provide 60 days' notice (November 1, 2026). Tenant pays $1,500 (correctly refusing the increase). You sue for the $300 difference. Tenant counterclaims for treble damages (3 × $300 = $900), plus attorney fees. You lose and owe the tenant $900 + attorney fees. You also could not evict for non-payment of the invalid increase.

Notice Delivery: Which Method Protects You?

ORS 90.323 does not specify how notice must be delivered, only that it be in writing. However, you must prove delivery. Recommended methods include:

Method	Proof of Delivery	Risk
Certified Mail (Return Receipt)	USPS green card with signature	Low—government-issued proof
Hand Delivery to Tenant	Tenant signature on copy	Low—direct acknowledgment
Posted on Unit Door	Dated photo of posting	Medium—tenant may deny seeing it
Email	Read receipt or delivery confirmation	Medium—tenant claims email lost
Text Message	Phone screenshot	High—courts may not accept as "writing"

Best practice: Use certified mail (return receipt) or hand delivery with written acknowledgment. This creates an indisputable record. If you rely on posted notices or email, photograph or screenshot the delivery, but expect the tenant to challenge it in court.

Common Calculation Mistakes (and How to Avoid Them)

Mistake #1: Using the Wrong CPI Index

Oregon law requires the CPI-U for the West Region. Many landlords incorrectly use:

• The national (U.S. city average) CPI-U
• The Portland-Salem-Eugene Metropolitan Statistical Area CPI
• The CPI-W (wage earner and clerical worker version)

These alternative indexes often show different percentage changes. For example, in 2024, the West Region CPI-U rose 2.4%, but the national CPI-U rose 2.6%. Using the national average would have overstated your allowable increase by 0.2 percentage points—a small error, but still an overage.

Fix: Always go to bls.gov/regions/west/ and select series CUUR0400SA0. Bookmark the page. Verify the region name on the data table before calculating.

Mistake #2: Calculating from the Wrong Baseline Month

The statute requires a "12-month basis," which means you compare the same month year-over-year, not month-to-month or custom periods.

For example, if you provide notice in October 2026 for an effective increase on January 1, 2027, you should use:

• September 2025 CPI-U West vs. September 2026 CPI-U West (the most recent available data)

You should NOT use:

• October 2025 vs. October 2026 (you don't have October 2026 data yet)
• An average of multiple months
• Data from a different time period

Fix: Use the most recent month of BLS data available at the time you prepare and deliver the notice. If BLS publishes data on the 11th of each month, check bls.gov on the 12th or later to ensure you have the latest available month.

Mistake #3: Not Rounding (or Rounding Incorrectly)

The statute does not specify rounding rules, but courts and the Oregon Bureau of Labor & Industries expect reasonable rounding to two decimal places, then communicated to tenants as a percentage (e.g., "Your rent will increase by 9.99%, effective January 1, 2027").

However, some landlords round during the calculation (creating compounding errors), or round up when the statute does not permit upward rounding beyond what the formula yields.

Fix: Calculate to four decimal places, then round the final percentage to two decimal places using standard rounding rules (0.5 and above rounds up, below 0.5 rounds down). Apply that percentage to the current rent to determine the new rent. Do not round the rent amount itself—if the calculation yields $1,650.47, that is the new rent (or you round to the nearest penny, not the nearest dollar).

Mistake #4: Increasing Rent Mid-Lease Without Meeting the Requirements

If a tenant has a fixed-term lease (e.g., 12-month lease expiring December 31, 2027), you cannot increase rent during the lease term unless the lease permits it. The 90-day notice requirement applies when the lease renews or when the tenancy converts to month-to-month.

For month-to-month tenancies or lease renewals, the 90-day notice must be provided before the increase takes effect.

Fix: Review the lease term carefully. Provide notice 90 days before the lease renewal date or before the first day of the month in which you want the increase to apply.

Mistake #5: Failing to Separate the CPI Calculation from the Rent Amount

Some landlords conflate the CPI percentage with the rent amount. For example, if the CPI calculation yields a 10% allowable increase and current rent is $1,500, the new rent is $1,500 × 1.10 = $1,650, not $1,500 + 10 = $1,510.

Fix: Use the formula: New Rent = Current Rent × (1 + CPI % + 7%). For 10% allowable increase and $1,500 current rent: $1,500 × 1.10 = $1,650.

Enforcement and Penalties

Who enforces Oregon's rent increase cap, and what are the consequences for violations?

Tenant Lawsuits (Most Common Enforcement)

Individual tenants can sue landlords directly for rent increase violations. They do not need to file a complaint with a government agency first.

• Claim type: Breach of contract or violation of statutory duty under ORS 90.323
• Recoverable damages: The overcharge amount (difference between the increase you imposed and the allowable increase)
• Treble damages: Three times the overcharge if the violation was "willful" (intentional or reckless)
• Attorney fees and court costs: If tenant prevails, landlord must pay tenant's attorney fees and court costs
• Venue: District Court or Small Claims Court (depending on claim amount)
• Statute of limitations: Not explicitly stated in ORS 90.323; likely governed by general contract law (2-6 years depending on claim type)

Example calculation: You increase rent from $1,500 to $1,700/month (13.3% increase) when the allowable increase was 10% ($1,650). The overcharge is $50/month. If the tenant pays for 12 months before suing, total overcharge is $600. If the court finds the violation was willful (e.g., you ignored ORS 90.323 entirely), treble damages are $1,800. Add attorney fees ($3,000–$5,000 likely), and you owe $4,800–$6,800+.

Government Enforcement (Rare but Possible)

The Oregon Bureau of Labor & Industries (BOLI) investigates tenant complaints but does not actively pursue landlords for isolated rent increase violations. However:

• Systematic violations (pattern of overcharges across multiple tenants) may trigger BOLI enforcement action
• BOLI can pursue civil penalties (amount not specified in statute, determined case-by-case)
• Violations can be grounds for license revocation for property managers or real estate professionals
• Egregious violations may trigger attorney general enforcement

In practice, BOLI enforcement is rare and reserved for bad-faith landlords or repeat offenders. However, it is possible, and you should not assume that only tenants can enforce the cap.

Recent Developments and 2026 CPI Context

As of October 2026, inflation and CPI trends are relevant to planning 2027 rent increases:

• 2024 West Region CPI-U increase: Approximately 2.4% (lower than national average)
• 2025 West Region CPI-U increase: Likely to be published in September/October 2026 (watch bls.gov)
• Expected allowable increase for 2027: Likely in the 9–10% range, depending on final CPI data (conservative estimate based on 2–3% CPI + 7%)

Landlords planning 2027 notices should monitor BLS releases in October 2026 to finalize their CPI calculations. Waiting until November to prepare notices may result in using December 2026 CPI data (if available), which is also acceptable.

Practical Compliance Checklist for Your Rent Increase Notice

Before sending a rent increase notice, complete this checklist to ensure compliance:

• ☐ Verify that the building is subject to ORS 90.323(2) (not built after 1/1/1990 as new building with no prior rent-controlled tenants)
• ☐ Check lease term—ensure lease renewal or month-to-month tenancy applies (not mid-lease increase unless permitted by lease)
• ☐ Obtain CPI-U West Region data from bls.gov/regions/west/ for the most recent 12-month period available
• ☐ Calculate 12-month CPI percentage change using the correct index (CUUR0400SA0)
• ☐ Add 7% to the CPI percentage to determine your allowable increase cap
• ☐ Decide what increase to impose (can be less than the cap, but not more)
• ☐ Calculate new rent amount using the formula: Current Rent × (1 + Allowable % Increase)
• ☐ Prepare written notice with current rent, new rent, effective date, and clear language
• ☐ Count 90 days from notice date to effective date (verify the math)
• ☐ Deliver notice via certified mail (return receipt), hand delivery (with signature), or other documented method
• ☐ Retain delivery proof (green card, receipt, photo, signed copy) for at least 3 years
• ☐ Document the CPI data source and calculation in your records (proves good faith if disputed)

Integrating Rent Increase Management Into Your Operations

For self-managing landlords with 2–75 units, manually tracking rent increases, CPI data, and 90-day notice deadlines across multiple leases creates compliance risk. A few operational steps reduce that risk:

• Lease renewal calendar: Maintain a spreadsheet or shared calendar with all lease renewal dates. Set alerts 120 days before each renewal so you have time to calculate and deliver notice.
• CPI tracking sheet: Create a simple table with the rent increase cap calculation for each year, updated annually when new BLS data is available. This becomes your reference document.
• Notice template: Use a standardized notice template that includes all required elements (current rent, new rent, effective date, CPI calculation reference) to reduce errors.
• Delivery log: Record every notice you send: date, method of delivery, proof of delivery, tenant name, unit, current rent, new rent. This is your defense if the tenant disputes receiving notice.
• Lease compliance review: Before each rent increase, confirm the lease allows it (or that the lease is expiring). Mid-lease increases can create liability if not permitted by the lease.

Property management platforms like LeaseBase's lease operations module can automate lease renewal tracking and generate rent increase notices with built-in CPI calculation, reducing the manual overhead and the risk of calculation errors.

Frequently Asked Questions

Q: Can I increase rent more than once per year?

A: No. ORS 90.323(2) applies to "a rent increase," implying a single increase per tenancy per year. If you increase rent once during a lease year, you cannot increase it again for 12 months. Some leases allow increases at lease renewal only; others allow month-to-month changes. Review your lease. If it is month-to-month, you could theoretically increase every month, but each increase must comply with the cap and the 90-day notice requirement. In practice, increasing more than once per year is rare and creates tenant friction; most landlords increase once annually at lease renewal.

Q: What if the CPI decreases year-over-year?

A: The statute does not prohibit negative CPI or deflation. If the CPI-U West decreases 2%, the allowable increase is -2% + 7% = 5%. You can still increase rent up to 5% even in deflationary periods. If deflation exceeds 7% (historically rare), you would have a negative allowable increase, meaning you could not legally increase rent. As of 2024–2026, deflation is not expected, and West Region CPI is likely to remain positive.

Q: If I own units in Oregon and another state, which CPI do I use?

A: You must use the West Region CPI-U for each Oregon unit and the applicable regional CPI for units in other states. Do not mix indexes. This is common for regional or multi-state landlords. Maintain separate calculations for each state's units.

Q: Does the rent increase cap apply to subsidized housing or Section 8 units?

A: Yes. ORS 90.323(2) applies to all residential tenancies except the narrow exemption for new buildings. Subsidized housing and Section 8 units are residential tenancies and are subject to the cap. However, your actual tenant-paid rent may be limited separately by subsidy rules or lease terms; the statute sets a ceiling, not a requirement that you increase by the maximum allowed. Always consult the subsidy program rules and your tenant's lease.

Q: Can I charge a "CPI adjustment fee" on top of the rent increase?

A: No. The statute caps the rent increase, not fees. However, any fee you charge in addition to rent would likely be challenged as an indirect circumvention of the cap. The safest approach is to limit your increase to the allowable amount and do not layer fees on top. Oregon courts have been skeptical of landlord fees that appear designed to evade statutory caps.

Q: I did not provide 90 days' notice. Can the tenant be evicted for non-payment of the (invalid) increase?

A: No. If you did not provide 90 days' notice, the increase is void. The tenant is not obligated to pay it. If you evict for non-payment of a void increase, the tenant will raise the ORS 90.323 violation as a defense, and the eviction will be dismissed. You will also expose yourself to a countersuit for treble damages. Do not attempt to evict based on an invalid rent increase.

Disclaimer

This article is for informational purposes only and does not constitute legal advice. Consult a qualified attorney for guidance specific to your situation. Rent increase laws are subject to change, and local ordinances in cities like Portland may impose stricter limits than state law. Verify all calculations and procedures with current statute text and professional counsel before implementing rent increases.

For links to official resources, see the Oregon landlord-tenant law resource center.