EHO Frequently Asked Questions

Application Process

How do I apply for Expanded Housing Option (EHO) development?

EHO development will require approval of an EHO permit, issued by the Zoning Division. Depending on the nature of the project, other permits, e.g., Residential or Commercial Building permit (and associated trade permits) or Land Disturbing Activity/Stormwater permit, will also be required. Upon project completion, applicants must file for a Certificate of Occupancy (CO) with the Zoning Division.

EHO permit applications will be filed online through Permit Arlington. To start an application, click “Create” and select “Zoning Application.”

What materials are required to be submitted for an EHO permit?

An application for an EHO permit must comply with the standards of §10.4 of the Zoning Ordinance, as well as other dimensional requirements noted in §3.2 of the Zoning Ordinance.

Minimum submission requirements include scaled floor plans, building elevations and sections, building location plats/surveys, and landscaping/tree preservation plans.

Can an applicant apply for EHO and other permits (e.g., building permits) at the same time?

EHO and other permits can be filed concurrently. However, a building permit cannot be issued until the EHO permit is issued.

How long is the review cycle for an EHO permit?

Upon application, staff will review the submission for completeness. The anticipated review cycle for compliance with zoning standards is 20 business days. Many permit applications will require one or more revisions and subsequent review cycles to meet the zoning standards.

Is there a fee for an EHO permit?

There is currently no fee for an EHO permit. A fee may be proposed in 2024.

Once issued, how long is an EHO permit valid?

An EHO permit does not expire.

How do I schedule a pre-submission meeting?

After July 1, interested applicants can contact the Zoning Division by email or phoneto set up a pre-submission meeting. Pre-submission meetings are encouraged but not required.

Annual Permit Cap

What is the annual cap on EHO permits?

The Zoning Ordinance provisions for EHO development include limits on the number of permits that can be issued in a calendar year (§10.4.7 of the Zoning Ordinance). These limits, or caps, are based on the relevant zoning district, as follows:

  • R-5: 7 permits per year
  • R-6: 30 permits per year
  • R-8, R-10, and R-20 (combined): 21 permits per year

These caps are per calendar year (January through December) and are in effect until June 30, 2028. Because the EHO provisions go into effect on July 1, 2023, the first calendar year of implementation will end on December 31, 2023. The caps will reset each year on January 1.

Which permit will count toward the cap, and when is it counted?

The annual caps will be based on the issuance of EHO permits. For example, no more than 30 EHO permits can be approved and issued in the R-6 zone per calendar year.

Will EHO permit applications be approved in the order they are submitted?

EHO permit applications will be reviewed based on the order they are received. However, applications may require revisions and multiple review cycles, so there is no guarantee that applications will be approved in the order they are received.

Will the number of permit applications and approvals for each zoning district be publicly available?

Yes. Information on the number of EHO permit applications and approvals in each zoning district will be provided on the EHO permit webpage. A user-friendly dashboard with information on EHO permits is also being created and will be available later this year.

If the cap for a zoning district is reached, what happens to in-process EHO applications located within in that zoning district? Will they still be reviewed? Will there be a queue of unapproved applications for the following year?

Any applications under active review when a cap is reached will be denied/rejected, citing the regulations in §10.4.7 as the reason. A new EHO application will need to be submitted in the following calendar year. Zoning staff will not be maintaining a queue or waiting list of applications.

If the number of EHO permits issued in a calendar year is below the Zoning Ordinance cap, will the difference roll over to the next year?


Will an applicant be limited to a certain number of applications or issued permits per year?


Is the cap based on the total number of dwelling units or does the total building/project count as one permit?

For by-right EHO development, each building (i.e., duplex or multifamily building or group of townhouse/semidetached dwellings) counts as one permit for the purposes of determining the cap.

Gross Floor Area

What spaces count as gross floor area (GFA), and how is it calculated?

The Zoning Ordinance defines gross floor area as “the sum of the area of the horizontal surface of the several floors of a building measured from the exterior faces of exterior walls, to include all floor area not defined as gross parking area.”

In general, all interior spaces that have a floor and are enclosed by walls and are not used for parking or maneuvering will be counted as gross floor area. This includes basements and attic spaces with floors. Learn More.(PDF, 140KB)

Are mechanical spaces excluded from GFA?

No. Mechanical spaces within areas that meet the definition of GFA are counted as GFA.

Are internal stairs and common areas counted as GFA?


Is GFA associated with an interior accessory dwelling (permitted with a semidetached or townhouse unit) included within the maximum GFA allowed for an EHO development?

Yes. The GFA of an accessory dwelling is also subject to the standards of §12.9.2.A(e) of the Zoning Ordinance.


How long will it take to complete a parking survey?

The parking survey process is expected to take 2-3 months, depending on the overall workload of County staff and contractors.

Is there a fee for parking survey?

There is currently no fee for requesting a parking survey. A fee may be proposed in 2024.

Do parking spaces located in both a front yard and a side yard (i.e., not directly in front of the building, but off to the side) count toward the maximum number of spaces that can be located within a front yard?

Yes. The limit on the number of parking spaces within a front yard extends the full width of the property located between the front wall of the dwelling and the street.

What are the parking requirements for an EHO semidetached or townhouse project that includes one or more accessory dwellings?

The main EHO dwelling(s) would be subject to the parking requirements in §10.4.6.A. Any accessory dwelling(s) would be subject to the parking requirements of §14.3.7.A. In general, if the main dwelling does not have a parking space, one space needs to be created. If the main dwelling has one or two spaces when the accessory dwelling permit is issued, those spaces need to be maintained.

Semidetached and Townhouses

For EHO semidetached or townhouse dwellings, is the average grade calculated for the entire site, or individual average grades for each unit?

Building height for townhouses and semidetached would be calculated from the existing grade at the four corners of the main/whole building (i.e., group of semidetached/townhouses). This is the required methodology for all R districts, per §3.1.6.A.1.

If a corner lot is subdivided for EHO semidetached or townhouse dwellings, do any of the newly created lots become interior lots, for the purpose of zoning standards?

No. If a corner lot is subdivided for EHO semidetached or townhouse development, the entire site will continue to be regulated as a corner lot.

Does each individual EHO semidetached/townhouse lot need to meet the lot coverage and main building footprint standards, or are these standards applied to the entire project site?

Lot coverage and main building footprint are applied across the entire EHO building site. Likewise, other zoning standards, such as the maximum GFA and minimum parking requirements, are applied over the entire main building and site.

Are two curb cuts allowed for two semidetached dwellings? Are three curb cuts allowed for three townhouse dwellings?

The EHO zoning standards for curb cuts only specify that they cannot exceed 17 feet in width. However, the County’s administrative standards for Driveway Entrances specifies a minimum separation of 25 feet between curb cuts. These standards may preclude the ability to achieve two or three curb cuts on a site, and applicants are encouraged to consult with the Department of Environmental Services.

For corner lots and through lots, can the individual entrances for EHO semidetached or townhouse dwellings face different streets?

Yes. Lots with frontage on multiple streets will satisfy the entrance requirement if each semidetached/townhouse dwelling has an entrance facing any street (or opening onto a porch facing the street). Through lots (lots with frontage on parallel streets) are not common, and streets with frontage on one street and one alley are not considered through lots.

Other EHO Standards

To receive the allowances for increased lot coverage or main building footprint for the provision of “one or more porches of at least 60 square feet (exclusive of any wraparound or side portion) facing a street,” does each porch need to be at least 60 square feet?

If multiple street-facing porches are provided, at least one porch needs to be 60 sq. ft. or more to meet the EHO standard for additional coverage, and at least 60 sq. ft. of the porch needs to be located within the front yard.

For a corner lot, does it matter which street the porch faces to be eligible for additional coverage?

For corner lots, an eligible porch can face either street to meet the EHO standard for additional coverage.

Is a balcony, screen porch, or covered porch counted as part of the main building footprint?

Yes. Any part of the main building that rests, directly or indirectly, on the ground is included in the main building footprint (§3.1.4.C of the Zoning Ordinance).

Can a four-unit EHO building be subdivided into two fee simple lots? This would be like two semidetached lots, each with two stacked dwellings.

No. The EHO regulations only allow subdivision for semidetached (two units) and townhouse (three units) developments. Semidetached dwellings are two units with one dwelling on each lot.

Four units within a multi-family building can be individually owned as condominiums, but the building cannot be subdivided into two.

The EHO regulations do allow semidetached dwellings to have an attached (interior) accessory dwelling. An accessory dwelling is effectively a portion of the main dwelling and cannot be conveyed independent of the main dwelling.

If a building includes multiple roof types (e.g., gable roof in front, flat roof in back), which is roof type used for measuring the maximum height?

The building height is measured from the average existing grade to the highest roof.