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Rolling first-certificate-of-occupancy exemptions in 2026 Four U.S. rent-cap regimes age every building individually — California 15 years, Oregon 15 years, Montgomery County 23 years, Washington State 12 years — and the day each unit graduates is the day the rules change.

· ~17 min read · California · Oregon · Montgomery County MD · Washington State

Four of the ten jurisdictions in the RentCeiling jurisdiction catalogue use a structure that catches landlords off-guard more often than any other rule we field questions about: a rolling first-certificate-of-occupancy exemption. A landlord who bought a 12-year-old Portland four-plex in 2024 and ran it through Oregon's 9.5% 2026 cap calculator that year would have come back with the message “exempt — building is under 15 years old.” Run the same building today, in 2026, against the same calculator and the answer flips: the building has crossed its 15-year anniversary, the exemption is gone, and the next notice issued is bound by ORS §90.323(1)(c)(B). Same building, same owner, same tenant — different rules, because the clock ticked.

This is a structural feature of four U.S. rent-cap regimes and not a transitional artifact. California AB 1482 at Cal. Civ. Code §1947.12(d)(4)(A) uses a 15-year rolling window. Oregon's SB 608, codified at ORS §90.323(2)(a), uses the same 15-year window. Montgomery County, Maryland's Bill 15-23 uses the longest 23-year window in the country. Washington State's HB 1217, at RCW §59.18.700(2)(d), uses a 12-year window — the shortest of the four.

The rest of the RentCeiling catalogue does not work this way. Costa-Hawkins at Cal. Civ. Code §1954.52(a)(1) uses a permanent post-February-1-1995 carve-out: a 1996 building is exempt forever, a 1994 building is covered forever, and the exemption status of any one California building under local rent control will not change in any future year. Washington DC's Rental Housing Act uses an even older permanent calendar anchor at September 1, 1978. Saint Paul uses 2004 as a permanent anchor. NYC's rent-stabilization regime under the 1969 Rent Stabilization Law and the 1974 ETPA does not turn on age at all — coverage is determined by building size, regulatory program (421-a, J-51), and pre-1974 construction status. Berkeley, San Francisco, and Oakland's local overlays are likewise tied to fixed historical dates that do not roll.

The four jurisdictions that do use rolling exemptions therefore behave differently from the rest of the catalogue at every renewal. Every January 1, every July 1, and every individual building's CoC anniversary, the answer to “is this unit covered?” can flip on a building that was exempt the day before. This post walks each of the four rolling regimes in order from shortest to longest window, explains the “graduation day” mechanics that attach when an exemption sunsets, contrasts the rolling structure with the permanent calendar anchors used elsewhere, and closes with the practical things a landlord whose building is approaching its anniversary should do before the clock ticks over.

The four rolling regimes at a glance

All four jurisdictions use the same structural device — tie the exemption to the issuance date of the first certificate of occupancy and let the window slide forward in time — but they pick different lengths and apply them to different rent-cap formulas. The differences in length are not arbitrary. They roughly track the political compromise each legislature struck between protecting new-construction incentives (long exemption) and protecting tenants in mid-aged buildings (short exemption).

Jurisdiction Rolling window Statutory anchor Cap when coverage attaches (2026)
Washington State 12 years RCW §59.18.700(2)(d) 9.683% residential cap (HB 1217)
California (AB 1482) 15 years Cal. Civ. Code §1947.12(d)(4)(A) 8.6%–8.8% regional, depending on MSA
Oregon (SB 608) 15 years ORS §90.323(2)(a) 9.5% statewide cap (2026)
Montgomery County, MD 23 years Bill 15-23, MoCo Code Ch. 29 5.4% Voluntary Rent Guideline (2026)

The 23-year Montgomery County window is the longest because the Maryland legislature made a deliberate choice in Bill 15-23 to insulate new construction long enough to amortize a typical commercial mortgage and one full debt-refinance cycle. The 12-year Washington State window is the shortest because HB 1217 was negotiated as a 2025 compromise that traded a long exemption for a higher allowable cap. California and Oregon's identical 15-year windows are not a coincidence — SB 608 was modeled on the AB 1482 exemption, and the drafters borrowed the language at ORS §90.323(2)(a) almost verbatim from §1947.12(d)(4)(A).

How rolling works mechanically

Every rolling exemption operates on the same three-step logic. The local building department issues a certificate of occupancy when the structure is built. That certificate carries a face date — for example, “Issued: April 14, 2011.” Each year on the anniversary of that date, the building grows one year older, and the question of whether the exemption applies on any given day is answered by subtracting the building's age from the statutory window.

The math is simple but the operational consequence is not: each building is on its own clock. A California portfolio with three buildings issued first CoC in 2008, 2012, and 2016 is in three different exemption states in 2026. The 2008 building hit its 15-year anniversary in 2023 and has been covered for three full notice cycles. The 2012 building hits its 15-year anniversary in 2027 — one more cycle of exemption. The 2016 building won't hit graduation day until 2031 — five more years of free pricing. The owner has to track three separate rule-sets and test each notice against the clock that applies on the date the notice is served.

The notice date matters because all four statutes test exemption status against the day the rent-increase notice is delivered to the tenant, not against the day the new rent takes effect. Cal. Civ. Code §1947.12(d)(4)(A) phrases this as “at the time of the rent increase” in the operative exemption language; Oregon's ORS §90.323(2)(a) uses parallel phrasing of “at the time the landlord serves notice.” The 90-day notice rule under Cal. Civ. Code §827(b) creates a real edge case: a notice served 89 days before a building's anniversary is governed by the exemption rules; a notice served the day after is bound by the cap. Landlords with buildings near anniversary often serve notices early to lock in the exempt status one last time.

Three more shared features run across all four regimes. First, the rolling clock cannot be reset by renovation. A building issued first CoC in 2010 stays a 2010 building forever, even after a $5 million gut rehab in 2022 that triggers a new permit cycle. Only an entirely new structure with its own first CoC starts a new 15-year (or 12-year, or 23-year) window. Second, the exemption is binary — either the unit is exempt today or it is not, with no graduated phase-in. Third, on graduation day the just-cause regime attaches simultaneously with the rent-cap regime, so a notice served on day 1 of coverage must comply with both the cap formula and the just-cause notice-content requirements at §1946.2 (California) or §90.427 (Oregon).

California: AB 1482's 15-year window at Cal. Civ. Code §1947.12(d)(4)(A)

Cal. Civ. Code §1947.12(d)(4)(A) reads, in operative part, that AB 1482's rent cap does not apply to “Housing that has been issued a certificate of occupancy within the previous 15 years.” The language is taken almost verbatim from the original 2019 statute and has been amended only modestly in subsequent legislation; the 15-year window has not been extended or shortened since the bill became law.

The exemption is one of seven categorical exemptions at §1947.12(d). The full list runs: (d)(1) deed-restricted affordable housing; (d)(2) a dormitory operated in connection with a higher-education institution; (d)(3) housing subject to a state or federal rent regulation that is more protective of the tenant; (d)(4)(A) the 15-year rolling first-CoC carve-out at issue here; (d)(5) the single-family-rental exemption with the §1947.12(d)(5)(B)(i) notice requirement; (d)(6) owner-occupied two-or-fewer-unit buildings; and (d)(7) housing subject to a local ordinance imposing a more restrictive cap. The 15-year carve-out is independent of all six others — a unit can qualify for the 15-year exemption alone, or stack it with the single-family-rental exemption, or with the deed-restricted carve-out, or with any combination.

A practical consequence of the seven-exemption structure: a building that loses its 15-year exemption on the anniversary of its first CoC may still be exempt under one of the other six grounds. A four-unit condominium project where each unit is owned by a natural person and rented under a §1947.12(d)(5)(B)(i) notice will keep its exemption past the 15-year mark on single-family-rental grounds. A 14-year-old deed-restricted affordable building loses the rolling exemption next year but stays exempt under §1947.12(d)(1).

The interaction between the rolling AB 1482 exemption and the permanent Costa-Hawkins exemption is the source of more confusion than any other AB 1482 question. They sit in different layers. Costa-Hawkins (Cal. Civ. Code §1954.52(a)(1)) controls whether local rent control reaches a unit; AB 1482 controls whether the statewide cap reaches it. A San Francisco building issued first CoC in 1998 is permanently exempt from SF Chapter 37 (post-Feb-1-1995 means Costa-Hawkins exempt) but was covered by AB 1482 from 2019 through 2013 (15 years from 1998 = 2013, before AB 1482 even existed) and is still covered by AB 1482 today. A San Francisco building issued first CoC in 2015 is Costa-Hawkins exempt from SF Chapter 37, and exempt from AB 1482 for the first 15 years, becoming AB 1482 covered on the 2030 anniversary — while remaining permanently SF Chapter 37 exempt. The two clocks tick independently.

The penalty cascade for serving an AB 1482 notice on a building that the landlord wrongly believed was still exempt is the same as for any over-cap notice. §1947.12(h)(2) voids the notice; §1947.12(h)(3) makes the landlord liable for the unlawful overage; the unit loses its §1946.2 just-cause-exemption defense; and the prevailing tenant collects attorney fees under §1947.12(h)(4). A landlord who is uncertain whether the 15-year clock has run should pull the certificate from the local building department before serving the notice — the cost of a public-records request is in single-digit dollars; the cost of an over-cap notice is treble damages plus fees.

Oregon: SB 608's 15-year window at ORS §90.323(2)(a)

Oregon's parallel exemption at ORS §90.323(2)(a) is the other 15-year regime in the country, and the operative language is closely modeled on the AB 1482 statute. The Oregon clause exempts “any dwelling unit if the first certificate of occupancy for the dwelling unit was issued less than 15 years before the date of the notice of the rent increase.”

The notice date is the testing date, same as in California. Oregon's universal 90-day notice rule at ORS §90.323(3) means a landlord serving notice in late March 2026 for a July 1, 2026 effective date is testing exemption against the late-March date. ORS §90.155 adds three calendar days when service is by first-class mail, which means a notice mailed on March 30 is presumed served on April 2 — and the exemption test runs against April 2.

Oregon's SB 608 has a single rent-cap formula at ORS §90.323(1)(c)(B): “an amount that exceeds 7 percent plus the consumer price index, as set forth in subsection (1)(c)(A), for the prior calendar year over a 12-month period.” ORS §90.323(1)(c)(C) imposes a hard 10% ceiling on top of that formula. The CPI input is the BLS West Region CPI-U-X (the all-urban-consumers index for the West Region), and the 12-month period is September-to-September of the prior calendar year. For 2026, that math produces a 9.5% cap statewide.

There is no local-overlay layer in Oregon — the SB 608 statewide cap is the only rent-cap rule that applies in Oregon. Portland, Eugene, Salem, Bend, and every other Oregon city and county is bound by exactly the same 9.5% number in 2026. The structural simplicity is one reason the 15-year exemption is more consequential in Oregon than in California: when a Portland building graduates, the landlord goes from zero rules to one rule. When a California building graduates, the landlord may already have been bound by a local overlay (San Francisco Chapter 37, LA RSO, Berkeley BMC 13.76, Oakland OMC 8.22, Santa Monica Charter Article XVIII, West Hollywood RSO, San Diego Tenant Protections Ordinance) that imposed a tighter cap from day one of construction.

The just-cause regime at ORS §90.427 attaches to a unit on the same day rent-cap coverage attaches. A tenant who has been in possession for 12 or more months gets the §90.427(5) no-cause-termination protection on graduation day, and the §90.427(8) one-month relocation requirement attaches to any §90.427(5)(b) landlord-or-family occupancy termination. The §90.427(8)(b) small-landlord exemption (fewer than four units) survives graduation, but applies only to landlord-or-family occupancy terminations — the no-cause termination protection at §90.427(5) attaches to every covered unit regardless of landlord size.

The penalty cascade at ORS §90.323(7) is closely parallel to the California structure: an over-cap notice is void and the landlord is liable for three months' rent plus actual damages plus attorney fees. The Oregon penalty also gives the tenant the right to recover possession — if the landlord has already evicted under a defective rent-increase notice, the tenant can move back in. That right does not exist in California's penalty cascade.

Montgomery County: Bill 15-23's 23-year window

Montgomery County, Maryland's Bill 15-23 was enacted in 2023 and codified at Montgomery County Code Chapter 29. The exemption at the implementing regulation excludes from rent-cap coverage any rental property whose first occupancy permit was issued within the prior 23 years — the longest rolling window in any U.S. rent-cap regime.

The 23-year window was chosen for two specific reasons. First, the typical commercial multifamily mortgage in 2023 ran 30 years amortizing with a 5- or 10-year balloon, and a 23-year exemption gives the developer space to refinance through one balloon and into a stabilized cash flow before the rent-cap regime attaches. Second, Montgomery County's 2026 Voluntary Rent Guideline of 5.4% — computed as the lower of the 6.0% statutory ceiling or CPI-U Washington-Arlington-Alexandria for the prior 12-month period plus 3 percentage points — is more restrictive than any of the other three rolling regimes' caps (9.5%, 8.6–8.8%, 9.683%). A long exemption traded against a tight cap is the same political bargain Washington State struck in HB 1217, on a different ratio.

The Montgomery County exemption is structurally simpler than the California or Oregon analogues. There is no equivalent of California's seven-exemption catalogue at §1947.12(d) — the 23-year first-CoC carve-out is one of a small number of exclusions, alongside subsidized housing, owner-occupied two-or-fewer units, and certain accessory dwelling unit categories. A Montgomery County building either is or is not covered, and the answer flips on the 23-year anniversary of its first occupancy permit.

The Bill 15-23 banking provision — up to 2 percentage points of unused capacity carried forward, hard 6% absolute ceiling on any single notice — only accumulates during periods of coverage. A building entering coverage on its 23-year anniversary starts at zero banked capacity. This is the rule throughout the four rolling regimes, but Montgomery County's longer window makes it especially consequential: a 22-year-old building has had no opportunity to bank, and on the day it becomes covered the landlord is bound by the current-year 5.4% cap with no carry-forward cushion. Compare with a Berkeley landlord whose unit has been covered since the 1980 Costa-Hawkins anchor — that landlord may have decades of banked capacity accumulated under SF §4.12 (in San Francisco) or BMC §13.76.110 (in Berkeley) and can release more than the current-year cap on a single notice within the per-notice ceilings.

Maryland Real Property §8-208's payment-interval notice rule (the rule at the state level for any rental of any size, statewide) requires that a rent-increase notice for a periodic month-to-month tenancy be served at least one full payment interval before the new rent takes effect. Montgomery County tightens this to a 90-day notice for any covered increase under Bill 15-23. On graduation day, the 90-day notice rule attaches alongside the cap.

Washington State: HB 1217's 12-year window at RCW §59.18.700(2)(d)

Washington State's HB 1217 was enacted in 2025 and is the newest of the four regimes. It established two separate caps with two separate structures: a residential cap of 9.683% in 2026 at RCW §59.18.700, and a flat 5% manufactured-housing cap at RCW §59.20.120. The first-CoC exemption applies only to the residential cap; the manufactured-housing cap has no first-CoC carve-out.

The residential 12-year exemption at RCW §59.18.700(2)(d) is the shortest of the four rolling windows. HB 1217 was the product of a contentious 2025 legislative session and the 12-year window was the compromise the residential-cap proponents accepted in exchange for a relatively high cap and a Department of Commerce notice-form requirement.

The 9.683% residential cap derives from RCW §59.18.700(1)'s formula: the lesser of 7% plus the September-to-September CPI-U Seattle-Tacoma-Bellevue or a hard 10% ceiling. The September 2025 CPI-U Seattle-Tacoma-Bellevue figure (BLS series CUURA423SA0, March-2025-released February-2025-base) of 354.824 against the 364.344 figure for September 2026 produces a 12-month change of 2.683%, plus the 7% additive, rounded to 9.683%, capped under the 10% statutory ceiling.

The manufactured-housing cap at RCW §59.20.120 is structurally different. It is a flat 5% with no CPI-indexing, no first-CoC carve-out, and no expiration. Every manufactured-housing space in Washington State, regardless of age, is bound by the 5% number. A 50-year-old mobile-home park and a newly-installed manufactured-housing space are both bound by exactly the same number. The first-CoC exemption discussion in this post applies only to the 9.683% residential cap, not to the 5% manufactured-housing cap.

HB 1217's residential cap also has an additional structural feature that the other three regimes do not: a July 1, 2040 sunset. The residential 9.683% cap and the 12-year first-CoC carve-out both expire on July 1, 2040 by statutory operation. If the legislature does not renew, every covered Washington residential rental returns to the unregulated baseline on that date. The manufactured-housing 5% cap has no equivalent sunset. A landlord doing long-range capital planning on a Washington multifamily property therefore has two clocks: the building's individual 12-year first-CoC clock, and the statutory 2040 sunset on the entire residential cap regime.

HB 1217 also imposes a categorical first-12-months protection at RCW §59.18.700(1) that overrides every other exemption: regardless of age, regardless of any other carve-out, no rent-increase notice may be served on a Washington residential tenant within the first 12 months of the tenancy. A 30-year-old, otherwise-exempt building with a tenant who moved in nine months ago cannot receive any rent-increase notice for the next three months. This is unique to Washington among the four rolling regimes — California, Oregon, and Montgomery County all permit a rent-increase notice within the first 12 months of tenancy provided the cap and notice-period rules are honored.

The graduation moment: what changes on day one of coverage

On the day a building's rolling exemption ends, four things change simultaneously. First, the rent in place on that day becomes the unit's lawful base rent under the rent-cap statute, and every increase from that day forward is bound by the cap formula. Second, the just-cause regime attaches — AB 1482 §1946.2 in California, ORS §90.427 in Oregon, the Bill 15-23 just-cause overlay in Montgomery County, the HB 1217 just-cause regime at RCW §59.18.690 in Washington State. Third, any banking provision starts accumulating from zero (banking did not run during the exemption period). Fourth, any notice-content requirement attaches — the §1947.12 cap-disclosure language in California, the ORS §90.323(1)(c)(D) cap-language in Oregon, the Department of Commerce notice form in Washington State.

The mechanics of the rent-in-place-as-base-rent rule deserve close attention. On day 1 of coverage, the rent that the tenant is currently paying becomes the base — not the rent that should have been charged under some hypothetical historical cap, not some Bureau of Labor Statistics index, not the market rent. Whatever the lease (or month-to-month tenancy) currently runs at on graduation day is the rent that all future cap-formula math runs against. A landlord who increased rent aggressively during the exemption period (legally, since no cap applied) carries that rent forward as the base, and the next regulated increase is computed from that elevated number.

This is one of the few features of the rolling regime that favors the landlord on graduation day. A landlord who knew the anniversary was coming and pushed rent to market in the 12 months before the date locks in a higher base for the entire post-graduation period. The same logic does not work in the other direction — a tenant who renewed at below-market during the exemption cannot retroactively reset to market on graduation day. The base is the rent that exists at the moment of graduation, full stop.

The just-cause regime change is more disruptive than the cap change for tenants who have been in place for several years. A 14-year-old California building with a tenant who has been in continuous residence for ten of those years gives the tenant zero just-cause protection through the exemption period. On graduation day, that tenant gets the full §1946.2(b) just-cause regime — and because the §1946.2(b)(1) 12-month or 24-month initial-occupancy carve-out is measured from the start of the tenancy, not from graduation day, the 10-year tenant gets the protection immediately. A landlord whose business plan included ending that tenancy without cause needs to act before graduation, not after.

How rolling exemptions differ from permanent calendar anchors

The rest of the RentCeiling jurisdiction catalogue uses permanent calendar anchors instead of rolling windows, and the difference is structurally significant. Costa-Hawkins' February 1, 1995 anchor at Cal. Civ. Code §1954.52(a)(1) is the canonical example: every California building issued first CoC after February 1, 1995 is permanently exempt from local rent control, and every building issued first CoC before that date is permanently covered. The exemption status of any one building will not change in any future year. It does not roll, will not sunset, and (absent legislative repeal) does not change.

DC's Rental Housing Act uses a parallel permanent anchor: every DC building issued first CoC after September 1, 1978 is permanently exempt from DC rent control; every building issued first CoC before that date is permanently covered. Saint Paul uses 2004 as a permanent anchor — a Saint Paul building issued first CoC after the May 2025 ordinance amendment effective date is permanently exempt. NYC's rent-stabilization regime under the 1969 RSL and 1974 ETPA does not turn on age at all, but uses a different permanent anchor: pre-1974 construction or inclusion in a 421-a/J-51 program.

Berkeley uses a hybrid: BMC Chapter 13.76 covers any unit issued first CoC before February 1, 1995 (the Costa-Hawkins anchor), with a small set of building-size carve-outs. San Francisco's Chapter 37 uses June 13, 1979. Oakland's OMC Chapter 8.22 uses December 31, 1982. Santa Monica's Charter Article XVIII uses April 10, 1979 — the earliest in the California catalogue. West Hollywood's WHMC Chapter 17.36 uses July 1, 1979. None of these dates roll.

The structural advantage of a permanent anchor for a landlord is certainty: a 1996-CoC California building will never be reached by Costa-Hawkins-controlled local rent control, and the owner's pricing strategy can be built on that certainty for the life of the asset. The structural advantage of a rolling exemption for a tenant is that mid-aged buildings eventually become covered, and the rent-controlled housing stock grows over time as the rolling regime catches up. A 2008-CoC Oregon building entered Oregon's covered stock in 2023; a 2010-CoC building enters in 2025; a 2012-CoC building enters in 2027. Each cohort that crosses its 15-year mark becomes a permanent addition to the covered inventory.

The structural disadvantage of the rolling regime for both sides is uncertainty around graduation day. A landlord can mismeasure the anniversary date by a few weeks and serve an over-cap notice that the penalty regime treats as fully unlawful. A tenant in a building approaching graduation may not know the date and may accept an “exempt” over-cap notice that, mailed two weeks too late, was actually governed by the cap. The cure for both sides is to pull the certificate from the local building department before any rent-increase notice changes hands — a public-records request that takes days, costs dollars, and produces an authoritative date that resolves the question for both parties.

If your building is approaching its sunset

The practical playbook for a landlord whose building is within 18 months of its rolling exemption sunset comes down to four steps, each of which we walk landlords through on the RentCeiling how-it-works page.

Step 1: Confirm the date of first certificate of occupancy with the issuing building department. Do not rely on the date the building was “built,” the date construction started, the date the building permit was issued, or the date the building was sold. The certificate-of-occupancy face date is the only date the rent-cap statute recognizes. Pull the certificate from the local Building & Safety division (LADBS in Los Angeles, DBI in San Francisco, the Planning department in Berkeley and Oakland, the Department of Permitting Services in Montgomery County, SDCI in Seattle, the local building official under ORS §455.057 in Oregon). The cost is in single-digit dollars; the legal weight is dispositive.

Step 2: If you intend to push rent before graduation, serve the increase notice with enough lead time to clear the anniversary by the longer of (a) the statutory notice period plus mailing-add days or (b) 30 days of comfort margin. A California §827(b) notice for an under-10% increase is 30 days plus §1013's 5-day mailing-add presumption (35 days total). An Oregon §90.323(3) 90-day notice plus §90.155's 3-day add is 93 days total. A Montgomery County 90-day notice with the Maryland §8-208 3-day add is 93 days total. A Washington State 90-day notice with the substituted-service add at RCW §59.12.040 is up to 95 days total. Beyond the statutory minimums, build in 30 days of comfort margin so a clerical error in date arithmetic does not flip an exempt notice into a covered notice.

Step 3: For tenants you do not intend to keep past graduation, end the tenancy under the exemption-period rules, not the post-graduation rules. During the exemption period, no-cause terminations remain available under the standard month-to-month rules in each state (California Civ. Code §1946 / §1946.1, Oregon §90.427(3) for first-year tenancies and the §90.427(8) owner-or-family carve-out otherwise, Montgomery County under the standard Maryland Real Property §8-402 rules, Washington State under RCW §59.18.200). On graduation day, all four regimes attach a just-cause overlay that eliminates the no-cause termination and replaces it with a closed list of allowed grounds. A landlord whose business plan called for ending a tenancy by reason of incompatibility, neighborhood concern, or simple landlord preference must do so before graduation or accept that the option no longer exists.

Step 4: After graduation, run every increase notice through the cap-formula calculation in the month it is served. The 2026 cap numbers (5.4% Montgomery County, 8.6–8.8% California, 9.5% Oregon, 9.683% Washington State residential) reset every year on different dates — January 1 in Montgomery County and Washington State, August 1 in California for the 2026-27 cap year, January 1 in Oregon. A notice that was within the cap on January 1 may exceed the cap on August 1 because the formula rebased. The RentCeiling calculator models all four regimes against the most recent BLS CPI release for the controlling MSA and returns the cap as of the notice date.

What this does not apply to

The rolling first-CoC exemption only matters for the four rent-cap regimes that use one. Six of the ten jurisdictions in the RentCeiling catalogue are governed by structurally different rules.

Costa-Hawkins and the California local overlays (LA RSO, SF Chapter 37, Berkeley BMC 13.76, Oakland OMC 8.22, Santa Monica Charter Art. XVIII, West Hollywood WHMC Chapter 17.36) all use permanent calendar anchors. A 1996-CoC LA-RSO-area building is permanently exempt from LA RSO; a 1985-CoC building is permanently covered. The status will not change in any future year.

DC's Rental Housing Act uses a permanent September 1, 1978 anchor. NYC's rent-stabilization regime under the 1969 RSL and 1974 ETPA uses pre-1974 construction or inclusion in a 421-a/J-51 program as the coverage test. Saint Paul uses a permanent 2004 anchor under the 2025 ordinance amendments. Washington State's manufactured-housing cap has no first-CoC exemption at all.

The four regimes that do use rolling exemptions therefore behave differently from every other jurisdiction in the catalogue at every renewal. The four rolling jurisdictions also behave differently from each other along three dimensions: window length (12 / 15 / 15 / 23 years), cap formula (5.4% to 9.683%), and just-cause-attachment timing. Any landlord with units across more than one of the four rolling regimes is running three separate clocks per portfolio, with the answer to “is this unit covered?” resolving differently each year.

The bottom line

A rolling first-certificate-of-occupancy exemption is a deliberate political compromise that rents the newest construction to landlords on free-pricing terms for a fixed window, then drops it into the cap regime once the window closes. The four U.S. regimes that use the device pick different windows (12 / 15 / 15 / 23 years) and apply them to different cap formulas (5.4% / 8.6–8.8% / 9.5% / 9.683%), but the underlying mechanic is the same: each building is on its own clock, the clock runs from the date on the first certificate of occupancy, and on the day the clock runs out the cap, the just-cause regime, the notice-content rules, and the banking baseline all attach simultaneously.

If you own units in California, Oregon, Montgomery County, or Washington State, your operational checklist is short and unforgiving: pull the certificate of occupancy from the issuing building department, mark the anniversary on a calendar two years out, decide before the year of graduation whether you want to push rent or end any month-to-month tenancies under the exemption-period rules, and serve any pre-graduation notice with a 30-day comfort margin beyond the statutory notice-period plus mailing-add days. The RentCeiling calculator will run the same numbers as fast as you can type the address, but the certificate-of-occupancy date is the input you have to verify against the public record before any calculation matters.

The four rolling regimes are also a useful mirror for the rest of the U.S. rent-cap catalogue. Permanent calendar anchors give landlords certainty for the life of the asset and lock the covered stock at whatever size it was on the anchor date. Rolling exemptions trade certainty for a slowly-growing covered stock and for the political durability of being able to point at the youngest buildings in the regulatory framework and say “these are still on free-pricing terms.” Both designs have constituents who will argue they are the right design. What both have in common is that the landlord whose building is at or near the line has to read the statute carefully and pull the documents that prove the date.

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Frequently asked questions

What is a rolling first-certificate-of-occupancy exemption?

It is a rent-cap exemption tied to the date the first certificate of occupancy was issued for a building, where the exemption window slides forward in time. A 15-year rolling exemption means a building that received its first certificate of occupancy 14 years and 11 months ago is exempt today, but the same building becomes covered the day it crosses the 15-year mark. Four U.S. rent-cap regimes use this structure: California AB 1482 at 15 years, Oregon SB 608 at 15 years, Montgomery County at 23 years, and Washington State at 12 years.

How is a rolling exemption different from a permanent post-construction-date carve-out?

A permanent carve-out fixes a calendar date: every building constructed after that date is permanently exempt, and every building constructed before is permanently covered. The Costa-Hawkins Rental Housing Act at Cal. Civ. Code §1954.52(a)(1) is the canonical example. A rolling exemption ages each building individually: a Portland building issued first CoC in 2010 was exempt under Oregon SB 608 in 2024, becomes covered on the 2025 anniversary of its CoC date, and stays covered forever after.

Does the AB 1482 15-year window restart when a building is renovated?

No. Cal. Civ. Code §1947.12(d)(4)(A) ties the exemption to the issuance of the first certificate of occupancy, not to the most recent renovation or reissued CoC. A substantial gut renovation that triggers a new building permit does not restart the 15-year clock; only an entirely new structure with its own first CoC starts a new 15-year window. The same rule applies in Oregon under ORS §90.323(2)(a) and in Montgomery County under the Bill 15-23 implementing regulations.

What happens to my unit's rent on the day the rolling exemption ends?

The rent in place on graduation day becomes the unit's new lawful base rent under the rent-cap statute, and every increase from that day forward must comply with the cap. In California under AB 1482, the next §1947.12(a) notice issued for the unit is constrained to the §1947.12(a)(1) cap (the lower of 5% plus regional CPI or 10%) measured against the graduation-day rent. In Oregon, ORS §90.323(1)(c)(B) caps the next increase at 7% plus the prior calendar-year September-to-September West Region CPI-U change, with a hard 10% ceiling. The just-cause regime under §1946.2 (California) or §90.392 / §90.427 (Oregon) attaches the same day.

Does the AB 1482 single-family-rental exemption stack with the 15-year first-CoC exemption?

They are independent. A unit can be exempt under either exemption alone or both together. The §1947.12(d)(5) single-family-rental exemption requires non-corporate-LLC ownership plus the verbatim §1947.12(d)(5)(B)(i) tenant notice; the §1947.12(d)(4)(A) first-CoC exemption applies only for the first 15 years from the building's first certificate of occupancy. They run on separate clocks and a unit losing one may still hold the other.

How does the Montgomery County 23-year window interact with the county's banking provision?

The 23-year exemption is a binary on/off: a Montgomery County rental newer than 23 years from initial occupancy is exempt from the entire Bill 15-23 framework, including the 6% absolute ceiling on any single rent-increase notice and the lower CPI-anchored allowable rent-increase. Banking does not apply during the exemption period — banking accumulates only during periods of coverage, so a building entering coverage on its 23-year anniversary starts with zero banked capacity.

Where does Washington State's HB 1217 12-year exemption come from?

RCW §59.18.700(2)(d) — adopted through HB 1217 — exempts any single dwelling unit certified for occupancy within the prior 12 years from the residential 9.683% rent cap at RCW §59.18.700. The 12-year window runs from the date the local jurisdiction issued the first certificate of occupancy. The manufactured-housing parallel at RCW §59.20.120 has no first-CoC exemption — every manufactured-housing space, regardless of age, is bound by the flat 5% annual cap.

If my building's exemption ends mid-tenancy, does the existing tenant immediately get just-cause protection?

Yes, in California and Oregon. AB 1482's just-cause regime at Cal. Civ. Code §1946.2 attaches to a unit on the day the rent-cap regime attaches, and §1946.2(b)(2) gives a continuing tenant just-cause protection from the moment the unit becomes covered. Oregon's just-cause regime at ORS §90.427 attaches the same day and gives a tenant who has been in possession for 12 or more months the §90.427(5) no-cause termination protection.

How do I prove the date of first certificate of occupancy if my records are missing?

Every U.S. local building department keeps the first certificate of occupancy on file as a public record. In California, request a copy from your city's Building & Safety division. In Oregon, contact the city or county building official under ORS §455.057. In Montgomery County, request from the Department of Permitting Services. In Washington State, request from the city's Department of Construction and Inspections (Seattle SDCI) under the state Public Records Act (RCW Chapter 42.56). The certificate face shows the issuance date — that is the date the rolling clock starts.