Accessory Dwelling Units Potential Zoning Options

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Watch this page for any updates on Accessory Dwelling Units regulations.

Should Fairfax City allow attached Accessory Dwelling Units in single-family neighborhoods? City Council and Planning Commission will be contemplating that question over the coming months. There will be public meetings examining this topic, and public participation is welcome.

What is an Accessory Dwelling Unit?

An Accessory Dwelling Unit (ADU) is a separate living quarters located within, or on the property of, another house. ADUs are full dwellings, containing both kitchen and bathroom facilities. They're called "accessory" because they're subordinate in size to the main house.

Attached ADUs are currently allowed in Fairfax City as long as the ADU is less than 35% of the house's size, has a maximum of two bedrooms, and either the main or accessory dwelling unit is occupied by the property owner.

Note: ADUs are subject to other standards as well, which are detailed in §3.5.5.D.1 of the City's Zoning Ordinance(External link).

The following types of housing arrangements are not considered ADUs, and would not be included in ADU zoning standards:

  • Renting to roommates, housemates, or tenants: The ability of homeowners to rent their properties would not be affected by ADU standards.
  • Changes to Single-Family Zoning: ADU standards would focus exclusively on Accessory units, and would not include changes to the types of housing units allowed in residential zoning districts.
  • Short-Term Rentals: Short-term rentals (i.e., Airbnb, etc.) are not allowed in the City of Fairfax. Any future change to the City's short-term rental policy would be considered separately from ADU standards.

City Policy Guidance

Some recent City policy documents have called for the City to reevaluate its ADU standards in order to make it easier for property owners to install ADUs.

The Comprehensive Plan(External link) contains a Housing Section that advocates for supporting a wide variety of housing types and for filling gaps in the City's housing supply. ADUs are mentioned in the Plan's Housing Section, specifically that the City should: "Revise zoning regulations to expand opportunities for accessory dwelling units, while ensuring they do not negatively impact surrounding neighborhoods." (Action H1.1.3, page 54)

In 2023, the City published a Housing Assessment(External link) that identified specific housing needs and provided strategic direction for addressing them. One of the Housing Assessment's recommendations - for both overall housing mix and for needs specific to seniors and accessible housing - is to: "Expand permissions for Accessory Dwelling Units." (Pages 25-27)

Watch this page for any updates on Accessory Dwelling Units regulations.

Should Fairfax City allow attached Accessory Dwelling Units in single-family neighborhoods? City Council and Planning Commission will be contemplating that question over the coming months. There will be public meetings examining this topic, and public participation is welcome.

What is an Accessory Dwelling Unit?

An Accessory Dwelling Unit (ADU) is a separate living quarters located within, or on the property of, another house. ADUs are full dwellings, containing both kitchen and bathroom facilities. They're called "accessory" because they're subordinate in size to the main house.

Attached ADUs are currently allowed in Fairfax City as long as the ADU is less than 35% of the house's size, has a maximum of two bedrooms, and either the main or accessory dwelling unit is occupied by the property owner.

Note: ADUs are subject to other standards as well, which are detailed in §3.5.5.D.1 of the City's Zoning Ordinance(External link).

The following types of housing arrangements are not considered ADUs, and would not be included in ADU zoning standards:

  • Renting to roommates, housemates, or tenants: The ability of homeowners to rent their properties would not be affected by ADU standards.
  • Changes to Single-Family Zoning: ADU standards would focus exclusively on Accessory units, and would not include changes to the types of housing units allowed in residential zoning districts.
  • Short-Term Rentals: Short-term rentals (i.e., Airbnb, etc.) are not allowed in the City of Fairfax. Any future change to the City's short-term rental policy would be considered separately from ADU standards.

City Policy Guidance

Some recent City policy documents have called for the City to reevaluate its ADU standards in order to make it easier for property owners to install ADUs.

The Comprehensive Plan(External link) contains a Housing Section that advocates for supporting a wide variety of housing types and for filling gaps in the City's housing supply. ADUs are mentioned in the Plan's Housing Section, specifically that the City should: "Revise zoning regulations to expand opportunities for accessory dwelling units, while ensuring they do not negatively impact surrounding neighborhoods." (Action H1.1.3, page 54)

In 2023, the City published a Housing Assessment(External link) that identified specific housing needs and provided strategic direction for addressing them. One of the Housing Assessment's recommendations - for both overall housing mix and for needs specific to seniors and accessible housing - is to: "Expand permissions for Accessory Dwelling Units." (Pages 25-27)

Questions

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  • Share Where does this policy change stand? There was a meeting scheduled to take place Nov of last year, but I see no follow-up on that. The link to the Comprehensive Plan is dead (Page not found). Is there a new link? Is there more information? Has a decision been made on the policy change? on Facebook Share Where does this policy change stand? There was a meeting scheduled to take place Nov of last year, but I see no follow-up on that. The link to the Comprehensive Plan is dead (Page not found). Is there a new link? Is there more information? Has a decision been made on the policy change? on Twitter Share Where does this policy change stand? There was a meeting scheduled to take place Nov of last year, but I see no follow-up on that. The link to the Comprehensive Plan is dead (Page not found). Is there a new link? Is there more information? Has a decision been made on the policy change? on Linkedin Email Where does this policy change stand? There was a meeting scheduled to take place Nov of last year, but I see no follow-up on that. The link to the Comprehensive Plan is dead (Page not found). Is there a new link? Is there more information? Has a decision been made on the policy change? link

    Where does this policy change stand? There was a meeting scheduled to take place Nov of last year, but I see no follow-up on that. The link to the Comprehensive Plan is dead (Page not found). Is there a new link? Is there more information? Has a decision been made on the policy change?

    MJS asked 7 days ago

    Staff is planning to recommend amending the Zoning Ordinance to remove the existing limitations on ADU occupancy (requiring either a disabled resident, or a resident age 55+).  We anticipate bringing those amendments forward to City Council this spring or early summer.  Considerations for potentially permitting detached accessory dwelling units are still being analyzed; updates will be posted on this Engage page when available.  Staff will hold another community meeting to discuss any potential options for detached ADUs.


    The link to the Comprehensive Plan has been fixed and can also be found here: City of Fairfax 2035 Comprehensive Plan(External link)

  • Share Good morning. Can i build a 20x24 addition/ADU attached to the back of my house for my elderly parents to live in? How long is the permit process? Beside engineering plans anything else I need to do? on Facebook Share Good morning. Can i build a 20x24 addition/ADU attached to the back of my house for my elderly parents to live in? How long is the permit process? Beside engineering plans anything else I need to do? on Twitter Share Good morning. Can i build a 20x24 addition/ADU attached to the back of my house for my elderly parents to live in? How long is the permit process? Beside engineering plans anything else I need to do? on Linkedin Email Good morning. Can i build a 20x24 addition/ADU attached to the back of my house for my elderly parents to live in? How long is the permit process? Beside engineering plans anything else I need to do? link

    Good morning. Can i build a 20x24 addition/ADU attached to the back of my house for my elderly parents to live in? How long is the permit process? Beside engineering plans anything else I need to do?

    Randygalliani asked about 1 month ago

    Thank you for your question. You will need to submit an application through the permit portal (link here(External link)). Please refer to the zoning webpage for additional information and if you have questions, you can email zoning@fairfaxva.gov(External link) or call 703-385-7820.

  • Share How do you take into account the negative impact on a neighbor's house who may be a very short distance from the ADU and be basically in the back yard of your house? It will also affect the value of your house having an ADU so close and the noise that will also affect the quality of your life. Fairfax, from what I read, has a minimum requirement of 2 acres which would address these concerns. on Facebook Share How do you take into account the negative impact on a neighbor's house who may be a very short distance from the ADU and be basically in the back yard of your house? It will also affect the value of your house having an ADU so close and the noise that will also affect the quality of your life. Fairfax, from what I read, has a minimum requirement of 2 acres which would address these concerns. on Twitter Share How do you take into account the negative impact on a neighbor's house who may be a very short distance from the ADU and be basically in the back yard of your house? It will also affect the value of your house having an ADU so close and the noise that will also affect the quality of your life. Fairfax, from what I read, has a minimum requirement of 2 acres which would address these concerns. on Linkedin Email How do you take into account the negative impact on a neighbor's house who may be a very short distance from the ADU and be basically in the back yard of your house? It will also affect the value of your house having an ADU so close and the noise that will also affect the quality of your life. Fairfax, from what I read, has a minimum requirement of 2 acres which would address these concerns. link

    How do you take into account the negative impact on a neighbor's house who may be a very short distance from the ADU and be basically in the back yard of your house? It will also affect the value of your house having an ADU so close and the noise that will also affect the quality of your life. Fairfax, from what I read, has a minimum requirement of 2 acres which would address these concerns.

    mowry1000 asked 2 months ago

    Fairfax City's Comprehensive Plan notes that if zoning standards are revised for Accessory Dwelling Units, that those standards should ensure that they "do no negatively impact surrounding neighborhoods." This could mean setting standards for a minimum distance from a property line, or required screening of ADU units, etc. - all these standards will be considered. There will be additional community meetings and public sessions on this topic so be sure to subscribe to this page for updates. Should you have specific concerns, feel free to reach out to staff or to City Councilmembers to ensure that those concerns may be understood.

  • Share Not a question, just a comment. I'd love to be able to build a standalone ADU on my city property. It's not that easy to incorporate an ADU into a split-level like mine because the ceilings are low and the floor plans do not lend themselves well to being subdivided. Retirees such as myself are property-rich but cashflow-poor, and being able to rent out an external ADU would be very helpful to everyone. I plan on staying in my home instead of relocating to a nursing facility in the future, and it would be ideal to be able to offer living space in an ADU as partial payment to a live-in caretaker. on Facebook Share Not a question, just a comment. I'd love to be able to build a standalone ADU on my city property. It's not that easy to incorporate an ADU into a split-level like mine because the ceilings are low and the floor plans do not lend themselves well to being subdivided. Retirees such as myself are property-rich but cashflow-poor, and being able to rent out an external ADU would be very helpful to everyone. I plan on staying in my home instead of relocating to a nursing facility in the future, and it would be ideal to be able to offer living space in an ADU as partial payment to a live-in caretaker. on Twitter Share Not a question, just a comment. I'd love to be able to build a standalone ADU on my city property. It's not that easy to incorporate an ADU into a split-level like mine because the ceilings are low and the floor plans do not lend themselves well to being subdivided. Retirees such as myself are property-rich but cashflow-poor, and being able to rent out an external ADU would be very helpful to everyone. I plan on staying in my home instead of relocating to a nursing facility in the future, and it would be ideal to be able to offer living space in an ADU as partial payment to a live-in caretaker. on Linkedin Email Not a question, just a comment. I'd love to be able to build a standalone ADU on my city property. It's not that easy to incorporate an ADU into a split-level like mine because the ceilings are low and the floor plans do not lend themselves well to being subdivided. Retirees such as myself are property-rich but cashflow-poor, and being able to rent out an external ADU would be very helpful to everyone. I plan on staying in my home instead of relocating to a nursing facility in the future, and it would be ideal to be able to offer living space in an ADU as partial payment to a live-in caretaker. link

    Not a question, just a comment. I'd love to be able to build a standalone ADU on my city property. It's not that easy to incorporate an ADU into a split-level like mine because the ceilings are low and the floor plans do not lend themselves well to being subdivided. Retirees such as myself are property-rich but cashflow-poor, and being able to rent out an external ADU would be very helpful to everyone. I plan on staying in my home instead of relocating to a nursing facility in the future, and it would be ideal to be able to offer living space in an ADU as partial payment to a live-in caretaker.

    Dave Marney asked 4 months ago

    Thank you for your comment!

  • Share What are we doing to balance the additional people ADUs will bring with infrastructure requirements? More people will need more services like police, fire, water, sewer, transportation, etc. on Facebook Share What are we doing to balance the additional people ADUs will bring with infrastructure requirements? More people will need more services like police, fire, water, sewer, transportation, etc. on Twitter Share What are we doing to balance the additional people ADUs will bring with infrastructure requirements? More people will need more services like police, fire, water, sewer, transportation, etc. on Linkedin Email What are we doing to balance the additional people ADUs will bring with infrastructure requirements? More people will need more services like police, fire, water, sewer, transportation, etc. link

    What are we doing to balance the additional people ADUs will bring with infrastructure requirements? More people will need more services like police, fire, water, sewer, transportation, etc.

    Redacted 2 asked 3 months ago

    Accessory dwelling units are not anticipated to develop at such a density that would heavily impact infrastructure. For major developments, City agencies review development proposals to assess potential impacts to infrastructure and seek mitigation measures from developers. While the City is not currently able to require mitigation for services, a fiscal impact study is completed for each development proposal to estimate whether cost burdens for services from the new development would exceed additional revenues.

  • Share What precisely is being proposed here? This is very vague and includes no details of what changes are being considered. While it addresses current ADU allowances, it does not address what is proposed, e.g. detached (separate structure) ADU dwellings; currently not permitted. If detached ADUs is what this is addressing, specifics such as property line set-backs, sewer, utility, etc need to be detailed. Also, if a detached ADU is what is being proposed, how does this fit into zoning and how would it be handled when sale of property occurs, e.g. would age requirements remain in place? on Facebook Share What precisely is being proposed here? This is very vague and includes no details of what changes are being considered. While it addresses current ADU allowances, it does not address what is proposed, e.g. detached (separate structure) ADU dwellings; currently not permitted. If detached ADUs is what this is addressing, specifics such as property line set-backs, sewer, utility, etc need to be detailed. Also, if a detached ADU is what is being proposed, how does this fit into zoning and how would it be handled when sale of property occurs, e.g. would age requirements remain in place? on Twitter Share What precisely is being proposed here? This is very vague and includes no details of what changes are being considered. While it addresses current ADU allowances, it does not address what is proposed, e.g. detached (separate structure) ADU dwellings; currently not permitted. If detached ADUs is what this is addressing, specifics such as property line set-backs, sewer, utility, etc need to be detailed. Also, if a detached ADU is what is being proposed, how does this fit into zoning and how would it be handled when sale of property occurs, e.g. would age requirements remain in place? on Linkedin Email What precisely is being proposed here? This is very vague and includes no details of what changes are being considered. While it addresses current ADU allowances, it does not address what is proposed, e.g. detached (separate structure) ADU dwellings; currently not permitted. If detached ADUs is what this is addressing, specifics such as property line set-backs, sewer, utility, etc need to be detailed. Also, if a detached ADU is what is being proposed, how does this fit into zoning and how would it be handled when sale of property occurs, e.g. would age requirements remain in place? link

    What precisely is being proposed here? This is very vague and includes no details of what changes are being considered. While it addresses current ADU allowances, it does not address what is proposed, e.g. detached (separate structure) ADU dwellings; currently not permitted. If detached ADUs is what this is addressing, specifics such as property line set-backs, sewer, utility, etc need to be detailed. Also, if a detached ADU is what is being proposed, how does this fit into zoning and how would it be handled when sale of property occurs, e.g. would age requirements remain in place?

    DACOX45 asked 5 months ago

    Thank you for your question regarding the ADU Community Meeting.

    There is not a specific policy being proposed right now – the meeting is in response to direction that City Council provided staff after a July work session that focused on Accessory Dwelling Units.  At that meeting, Council asked staff to:

    1. Eliminate the existing requirement that ADU occupants be aged 55+, or have a disability; and
    2. Investigate whether allowing Detached Accessory Dwelling Units would be beneficial to the City.


    This second item will be the Community Meeting’s major discussion point.  The meeting’s purpose is to gauge community sentiments regarding many of the issues you mentioned.  We plan to discuss Detached ADUs in general, and also potential options for ADU standards such as setbacks, size limitations, parking, etc. – similar items to what you mention in your question.  There’s little detail right now because we would like to solicit community feedback before reporting back to City Council and Planning Commission.

    I hope you’re able to attend the community meeting – should you have any further questions, please let us know.

Page last updated: 31 Mar 2025, 01:03 PM