Green Area Ratio - Determining Applicability

GAR Phase In period
Who Must Comply

The Green Area Ratio (GAR) applies to new buildings requiring a Certificate of Occupancy and to additions or interior renovations of existing buildings when construction costs exceed 100% of the assessed building value within a 12-month period.

Properties within the R, RF, USN, STE, HE, WR-1, and WR-6 zoning districts are exempt from GAR, and no exemption application is required.

Exemptions

Projects in other zoning districts may qualify for GAR exemptions under applicable zoning regulations, including 11 DCMR Subtitle C § 601.3:

Buildings that do not require a Certificate of Occupancy, including single-family residences.
Municipal wastewater treatment facilities operated by DC Water.
Interior renovations that increase gross floor area by no more than 10% and involve only minor exterior alterations, such as replacing doors, windows, or mechanical equipment.
Certain interior renovations within the Central Employment Area where the existing and proposed roof cannot support the required green roof loading.
Qualifying historic resources, except where an addition increases the building's gross floor area by 50% or more.
Certain conversions of existing floor area to residential use in qualifying Neighborhood Mixed-Use (NMU) and Downtown (D) zones, pursuant to 11 DCMR Subtitle H § 200.5 and Subtitle I § 102.6.

Exemption Application Process

Applicants requesting an exemption must complete the GAR Exemption Status Application (August 2026) and upload it to the Supporting Documents folder in DOB's ProjectDox for review and approval by the Office of Zoning Administration (OZA).

If the project requires stormwater management review, or as requested by DOEE, the approved exemption must also be uploaded to the Surface and Groundwater System (SGS).

If an exemption is not approved, a complete GAR plan package must be submitted through SGS. See Design Development and Submittal.

For questions about GAR applicability or exemptions, contact DOB’s Office of Zoning Administration at [email protected].

GAR cistern

Transition Period

GAR requirements became effective October 1, 2013. Certain projects with prior building permit filings or unexpired approvals may qualify for transition exemptions.

For additional information, refer to the GAR Transition Exemption Application or contact DOB's Office of Zoning Administration at [email protected].

See the GAR regulations for additional guidance on where GAR does and does not apply.