Certificate of Occupancy Is Required Before Moving Into a New Home Under IRC 2024

Quick Answer

Under IRC 2024 Section R110, no building or structure shall be used or occupied, and no change of occupancy of a building or portion of a building shall be made, until the building official has issued a certificate of occupancy. The CO is the building official’s written confirmation that a completed building complies with the provisions of the applicable code and is safe for its intended use. Occupying a building before the CO is issued can result in fines, forced vacation of the premises, insurance coverage issues, and complications with mortgage funding.

Under IRC 2024, the CO is not a formality—it is the legal authorization to occupy the building.

What IRC 2024 Actually Requires

Section R110.1 prohibits occupancy of any newly constructed or renovated building regulated by the IRC until the building official issues a certificate of occupancy. The CO is issued only after all final inspections have been completed and approved, all required inspections throughout the construction process have been passed, and the inspector has confirmed that the completed structure or work substantially conforms to the permitted plans and the adopted code.

Section R110.3 specifies what information the CO must contain: the building permit number; the address or legal description of the property; the description of the portion of the building for which the certificate is issued; the name and signature of the building official; the edition of the code under which the permit was issued; the use and occupancy; the type of construction; the design occupant load; the sprinkler system designation; and, if a temporary certificate is issued, a statement that the temporary certificate is issued for a period not to exceed 180 days, during which time any safety hazards must be corrected.

A temporary certificate of occupancy (TCO) may be issued under R110.4 before the entire project is complete, if the building official determines that substantial completion has been achieved and that the portion to be occupied is safe for occupancy. TCOs are common in custom home construction where exterior landscaping, certain finish work, or non-life-safety systems may still be in progress. The TCO specifies which deficiencies remain and the timeframe for correcting them. Allowing a TCO to expire without completing the outstanding work is a code violation.

Section R110.5 addresses existing buildings. When a change in use or occupancy is proposed for a building that was previously issued a CO for a different use, a new CO must be obtained before the new use begins. This is most common in residential real estate transactions where a building previously used as a single-family home is being converted to a duplex, or where an existing building is being converted to include an ADU. Each use change requires review to confirm the building meets the code requirements applicable to the new occupancy.

The building official is also authorized under R110 to revoke a CO where it was issued in error, where it was issued on the basis of incorrect information, or where the conditions of the CO have not been met. A revoked CO triggers the same prohibition on occupancy as if no CO had been issued at the outset.

Why This Rule Exists

The certificate of occupancy is the final checkpoint in the building permit and inspection system. It confirms that all required inspections were conducted and approved, that the structure was built according to the approved plans, and that the building official has made a professional determination that the building is safe for occupancy. Without this final confirmation step, the inspection system would be incomplete—a building could theoretically pass all intermediate inspections but then have significant work done after the last inspection that makes it unsafe.

The CO also serves an important legal and financial function beyond the building inspection system. Mortgage lenders typically require confirmation that a CO has been issued before releasing final loan funding on a construction loan. Title insurance companies flag the absence of a CO as a title defect. Homeowner’s insurance policies sometimes contain exclusions or coverage limitations for losses occurring in a building that was occupied without a CO. The CO provides the legal foundation for all these downstream financial relationships.

For rental properties, the CO has a direct effect on the landlord-tenant relationship. In most states, a landlord cannot legally collect rent for a residential unit that does not have a valid CO. Courts have held in many jurisdictions that lease agreements for units without COs are unenforceable, and tenants may be entitled to recover rent paid for occupancy of an un-certificated unit. Property managers and landlords who convert spaces to rental use without obtaining the applicable CO face significant legal exposure.

What the Inspector Checks at Rough and Final

The final inspection that leads to CO issuance is the most comprehensive single inspection in the permit process. The inspector arrives with the approved permit documents and the inspection record showing all prior inspections and their outcomes. If any prior inspection is listed as rejected and not subsequently approved, the final inspection cannot be approved and the CO cannot be issued until the rejection is resolved.

During the final inspection for a new single-family home, the inspector typically verifies: smoke alarms in all required locations per IRC R314 (in each sleeping room, outside each sleeping area, and on each story); carbon monoxide alarms in required locations per IRC R315; proper installation and operation of all required egress windows in sleeping rooms; handrails and guardrails on all required stairs and elevated walking surfaces; proper installation of the HVAC system, including thermostat operation, filter access, and equipment labeling; gas appliance operation and proper venting; water heater temperature-pressure relief valve installation and discharge pipe routing; proper grading away from the foundation at exterior; required address numbers visible from the street; and completed fire-separation assemblies in attached garages.

For additions and alterations, the final inspection scope is limited to the work authorized by the permit. The inspector confirms that the permitted work is complete, matches the approved plans, and that all inspections for the permitted work have been approved. Pre-existing conditions in portions of the building outside the permit scope are generally not subject to upgrade requirements unless the alteration triggers a code-required upgrade by another provision.

What Contractors Need to Know

The CO is the last deliverable on any permitted residential project, and it is the contractor’s responsibility to ensure that all conditions precedent to CO issuance are met. Creating a pre-final inspection punch list that covers every item the inspector will check—and completing that punch list before calling for the final inspection—significantly reduces the chance of a rejected final inspection that delays CO issuance.

Contractors should maintain a tracking log of all inspections called, approved, and rejected throughout the project. When the final inspection is called, the building official will review the complete inspection history. Any rejected inspection that was not subsequently re-inspected and approved is a flag that must be resolved before the CO can issue. Discovering a forgotten rejected inspection during final inspection is avoidable with proper record-keeping during construction.

Temporary COs can be a useful tool to allow a homeowner to move in while punch-list items are being resolved, but contractors who allow TCOs to expire without completing outstanding work expose both the contractor and the owner to code enforcement action. Build TCO completion deadlines into project schedules and treat them as firm commitments. The building official has authority to revoke the TCO and order vacation of the building if the outstanding items are not completed within the specified period.

Contractors who perform work under a permit and then move on to other projects before the CO is issued should ensure that the owner or their representative is managing the CO process. Leaving a project without a CO, even if construction is complete, is an open permit that can become a problem for the contractor when the permit authority follows up on the status of incomplete permits in their system.

What Homeowners Get Wrong

The single most common homeowner error is scheduling a move-in before the CO is in hand. Contractors and real estate professionals sometimes present the CO as a formality that will “follow shortly” after move-in, allowing closing and move-in to proceed before final inspection. This creates real legal and financial risk. Homeowner’s insurance that does not cover losses in a building occupied without a CO is not theoretical—insurance companies have successfully denied fire and casualty claims on this basis. A closing that occurs before the CO is issued may also trigger a condition of the construction loan that prevents the lender from releasing final funding.

Homeowners also frequently confuse the CO with the final inspection approval. The final inspection approval is the inspector’s field determination that the work is acceptable. The CO is a separate document issued by the building department after the final inspection approval and after any applicable administrative processing is complete. In some jurisdictions the CO is issued on the spot at the conclusion of a successful final inspection; in others it may take several business days for the document to be processed and issued. Confirm with the building department what the typical timeline is between final inspection approval and CO issuance so move-in can be planned accordingly.

For renovation projects, homeowners sometimes assume that because they are not building a new structure, no CO is required. Under R110.5, any change in use or occupancy requires a new CO. Converting a portion of a single-family home to an accessory dwelling unit, converting a garage to living space, or adding a bathroom all constitute changes that may require CO issuance once complete.

State and Local Amendments

California requires a certificate of occupancy for all new residential construction and for most additions and alterations. California also has a provision under Health and Safety Code Section 17980.7 that allows local enforcement agencies to red-tag a building and order it vacated for life-safety hazards even if it has a CO, if the building has subsequently fallen into a condition that endangers occupants. The CO does not confer permanent immunity from code enforcement.

New York City has its own certificate of occupancy system under the NYC Building Code that is more complex than the IRC model. NYC issues different CO types for different construction vintages and uses, and properties can have partial COs that cover portions of the building built under different permit applications. When purchasing property in NYC, a complete CO review by a title professional familiar with NYC building records is essential.

Texas and several other states allow certain local jurisdictions to opt out of mandatory CO requirements for residential construction, though most larger cities and counties maintain CO requirements as a local ordinance regardless of state minimums. In rural unincorporated areas, the absence of a building department means there may be no CO requirement at all, which can complicate financing and insurance for homes in those areas.

When to Hire a Professional

If you are purchasing a home that does not have a CO on record with the local building department—which may be discoverable through the city or county’s online permit search system—consult a real estate attorney before closing. The absence of a CO may indicate unpermitted construction, construction that failed inspection, or a building that predates CO requirements. The legal and financial consequences of owning a home without a CO depend heavily on local law and the reason the CO is missing.

Property owners who have received notice that their CO has been revoked, or who are facing code enforcement action related to occupancy of a building without a CO, should consult both a code consultant and an attorney. The process for reinstating a CO typically involves permitting any unpermitted work, passing all required inspections, and correcting any identified violations. A code consultant or permit expediter can manage this process more efficiently than a property owner unfamiliar with the permit and inspection system.

Contractors who manage the CO process as part of a construction contract should have a clear contractual provision defining when the contractor’s obligation is complete—whether at CO issuance, at final inspection approval, or at substantial completion as separately defined. Ambiguity in this provision can lead to disputes where the owner claims the CO is the contractor’s responsibility and the contractor claims the contract was complete at substantial completion regardless of CO status.

Common Violations Found at Inspection

• Smoke alarms missing from required locations per IRC R314: not installed in each sleeping room, outside each sleeping area, or on each story of the dwelling.
• Carbon monoxide alarms absent in required locations per IRC R315 where fuel-burning appliances or attached garages are present.
• Egress window in a sleeping room that does not meet minimum net clear opening area, minimum height of 24 inches, minimum width of 20 inches, or maximum sill height of 44 inches above the finished floor.
• Temperature-pressure relief valve on the water heater without a compliant discharge pipe routed to an approved termination point.
• Prior inspection in the permit record showing a rejection that was never re-inspected and approved, preventing CO issuance until the rejection history is resolved.
• Building occupied before CO issuance, discovered by inspector during final inspection or by code enforcement following a neighbor complaint.
• Temporary CO expired without completion of the outstanding deficiencies identified in the TCO, triggering code enforcement action and potential order to vacate.
• Change of occupancy—such as garage conversion to living space or ADU addition—completed without obtaining the required change-of-occupancy CO.