NYC unveils rules to legalize basement & cellar apartments; public hearings Dec. 11–12
NYC Basement Legalization ATR Pilot Program
Published: Nov 12, 2025
What the ATR pilot does
The Authorization for Temporary Residence (ATR) pilot creates a supervised path to bring eligible basement and cellar apartments into full legal compliance. Owners enter the program, keep baseline safety in place, complete code/zoning upgrades on a set schedule, and ultimately obtain an amended Certificate of Occupancy. The aim is to raise safety standards without widespread displacement while converting informal units into lawful homes.
Temporary occupancy while owners legalize
If an apartment meets baseline safety at entry, tenants may remain during the legalization process. Work is sequenced through a Tenant Protection Plan and inspections to ensure conditions stay safe as upgrades are installed.
How SLK Buildings coordinates your ATR legalization (with our in-house Registered Architect)
We manage the end-to-end path from “informal” to legal while you stay on schedule and tenants stay safe. Our in-house RA serves as Applicant of Record and leads all filings.
What we do
- Eligibility & zoning check: verify pre-4/20/2024 occupancy, pilot district status, flood-risk screening, and any zoning constraints.
- Basement vs. cellar determination: site measurements, spot elevations, light/air and clear-height review.
- Life-safety plan: egress strategy, smoke/gas alarms, boiler separation, and required upgrades (e.g., sprinklers, flood-water sensors).
- Engineering/MEP coordination: structural letters, mechanical/ventilation, plumbing (including NFPA 13D/13R feasibility where applicable).
- Tenant Protection Plan (TPP): sequencing work in occupied homes; right-to-return documentation if temporary relocation is required.
- Filings & permits: ATR application, Alteration filings for the legalization scope, required special inspections, and DOB/HPD interfaces.
- Milestone management: we calendar, submit, and track each ATR checkpoint through to the amended Certificate of Occupancy.
- Close-out: inspections, sign-offs, and amended C of O; ATR exit once the C of O is issued.
Typical deliverables
- Eligibility memo + district/flood map exhibits
- Code compliance matrix (egress, fire-rating, alarms, heating)
- Permit drawings (architectural, structural, MEP) and details
- TPP and safety sequencing plan
- Milestone schedule and owner checklist
- Final C of O package and ATR exit confirmation
What we need from you
- Proof the space existed before April 20, 2024 (photos, leases, utility records, etc.)
- Any prior plans/permits or surveys
- Owner authorization and access for site measurements
Disclaimer: SLK Buildings is an independent, private consultancy. We are not affiliated with or acting on behalf of any city, state, or federal agency. Our role is to coordinate filings and provide technical guidance to homeowners and industry professionals as they navigate NYC Department of Buildings (DOB), HPD, and related code and zoning requirements. Eligibility for programs (including ATR), permit approvals, and timelines are determined solely by the relevant agencies and may change. Our materials are informational and do not constitute legal advice; consult an attorney for legal questions.
No penalties if milestones are met
Owners accepted into ATR can pursue legalization without penalties tied to prior illegal occupancy, provided they meet all milestone deadlines and requirements. Missing milestones or safety lapses can jeopardize program standing and benefits.
Who qualifies
Eligibility hinges on three pillars: the unit existed before the law’s cutoff date, it’s located in designated community districts named in Local Law 126, and it meets baseline safety at application. Properties in mapped flood-risk areas are not eligible.
Units existing before April 20, 2024
The apartment must have been in existence prior to April 20, 2024. Documentation such as dated photos, leases, utility records, or prior plans can help establish that the space predates the cutoff.
Covered community districts under Local Law 126
Only units within the community districts listed in Local Law 126 can enter ATR. This targeted geography focuses resources where below-grade apartments are most prevalent and where the city authorized this pilot approach.
Not eligible: properties in flood-risk areas
Homes in flood-prone zones are excluded due to life-safety risks unique to below-grade spaces. Applicants should confirm flood-risk status early; ineligible properties cannot participate in ATR.
Safety requirements at entry
Before acceptance, units must show baseline protections: working detectors, heat, compliant egress, and proper separation from mechanical hazards. These measures ensure occupants are protected while additional upgrades are planned and permitted.
Smoke & gas alarms, central heating, egress
Apartments must have functioning smoke and gas alarms, reliable central heating, and an egress path that meets code. These basics reduce fire and environmental hazards and ensure occupants can exit safely in an emergency.
Separation from boiler equipment
Where mechanical or boiler rooms adjoin the apartment, adequate wall/door separations and fire-rating requirements apply. This limits heat, fire, and carbon monoxide risks while legalization work progresses.
Additional upgrades: sprinklers, flood-water sensors
As projects advance, many below-grade apartments will need enhanced life-safety measures. Common requirements include sprinkler installations and flood-water sensors, along with any project-specific fire-protection or ventilation improvements.
Timeline, deadlines, and how to apply
After the rules are finalized, owners submit applications to the Department of Buildings. Accepted projects follow a scheduled sequence – design, permitting, construction, inspections -ending with an amended Certificate of Occupancy.
Apply by April 20, 2029 via DOB
Applications open once the final rules are in effect. Owners must apply on the DOB portal no later than April 20, 2029. Early submission helps align design and permitting with milestone deadlines.
10-year path with milestone checkpoints
ATR provides up to a 10-year window to reach full compliance, with interim checkpoints set by DOB. Hitting each milestone on time preserves eligibility, penalty relief, and authorization for temporary residence.
Tenant protections
The program is designed to improve safety while limiting disruption for residents. Occupancy is permitted when safe, with protections for tenants if temporary relocation is required.
Right to remain during work when feasible
Where baseline safety can be maintained, tenants stay in place while work proceeds under a Tenant Protection Plan. Inspections verify that living conditions remain compliant throughout construction.
Right to return if temporary relocation is required
If short-term relocation is necessary for safety or construction, tenants are afforded a right to return once improvements are complete and the unit is cleared for occupancy.
After construction is complete
When all work is finished and inspections are passed, owners file to update the building’s legal records to reflect the new residential configuration.
Alteration application & amended Certificate of Occupancy
Legalization culminates in an alteration filing and issuance of an amended Certificate of Occupancy documenting the apartment as a lawful residence.
Exit from ATR once C of O is issued
After the amended Certificate of Occupancy is granted, the property exits the ATR program. The apartment is now recognized as legal and no longer subject to the pilot’s conditions.
How this differs from the prior BK pilot (BACPP)
Unlike the earlier East New York/Cypress Hills loan program, ATR is a citywide framework (limited to designated districts) centered on safety, milestones, and final legalization—rather than a single-neighborhood financing initiative.
Citywide scope vs. CD5-only loans/assistance
BACPP was confined to Brooklyn Community District 5 and paired technical help with low- or no-interest loans. ATR applies across multiple districts citywide named in Local Law 126 and focuses on authorization to remain while legalizing.
Lessons learned and financing context
The prior pilot demonstrated that targeted standards and technical coordination can move units from informal to legal. ATR builds on those lessons with clearer safety benchmarks and timelines. While ATR itself is not a loan program, owners can still pursue private financing or city resources where available to complete the required upgrades.