Everything homeowners need to know about building an accessory dwelling unit in Richmond - size limits, permits, and how the city's 2023 by-right ordinance compares with the zoning rewrite still working its way through City Council.
Last verified: September 2026
6/10 · Moderately ADU-friendly
1/3 of home*
Max ADU size
Varies by district*
Max height
Not required
Owner-occupancy
By-right
Permit type
This page summarizes Richmond's Zoning Ordinance (Chapter 30) ADU provisions, adopted September 25, 2023, plus Virginia's new statewide ADU law, for general reference - it is not legal advice. Regulations change, and Richmond's larger zoning rewrite is still in progress - always confirm current requirements with the Department of Planning and Development Review before designing or applying for permits. See sources below.
Zoning & size requirements
What you're allowed to build
ADU type
Max size
Max height
Notes
Detached (new build or garage conversion)
One-third (1/3) of the main single-family dwelling's floor area, or 500 sq ft, whichever is greater
Set by the underlying zoning district, not a separate ADU-specific number
Requires fire department access from the main street or rear alley, and gets its own street address
Attached (addition or interior conversion with separate entrance)
Same 1/3-of-home-or-500-sq-ft formula
Same as primary structure
Changes the primary dwelling's classification to a Detached Two-Family Dwelling
Allowed zoning districts & size math
One ADU is allowed by-right in all residential zoning districts, on the same lot as an existing or proposed single-family dwelling. Because the size cap scales with your home (1/3 of its floor area, with 500 sq ft as the floor, not the ceiling), a small house effectively caps you closer to 500 sq ft, while a larger home unlocks a bigger ADU. Height, setbacks, and lot coverage all follow the standard rules for your specific zoning district rather than a single citywide ADU number. Confirm your parcel's district and the exact size math with Zoning Administration.
Additional standards
Setbacks, parking & other rules
Setbacks
Follow the underlying zoning district's standard setback, lot-coverage, and height rules - there's no separate, smaller ADU-specific setback citywide
Parking
No dedicated off-street parking space is required specifically for the ADU
Units per lot
1 ADU permitted in addition to the primary single-family dwelling
Owner-occupancy
Not required under Richmond's own ordinance or its official permit guidance
Utilities
An attached ADU's utilities generally run through the primary dwelling (exceptions need Commissioner of Buildings approval); a detached ADU can share utilities with the main house or have its own
Building code
Must meet Virginia Residential Code dwelling-unit standards, including egress, ceiling height, and sanitation requirements
Ordinance history
How Richmond's ADU rules got here
2020Richmond 300 master plan adopted. The plan's "Big Moves" set rewriting the city's zoning code, unchanged in its fundamentals since 1976, as a long-term priority.
Sep 2023ADUs made by-right. Before this, an ADU legally required a waiver and an individual City Council vote for approval. City Council's ordinance allowed one ADU per lot administratively, in all residential zoning districts, with no special-use permit or Council vote needed.
2025"Code Refresh" zoning rewrite advances. Richmond released draft zoning ordinance language implementing Richmond 300, including a proposal to allow a duplex plus an ADU by-right on more lots and to raise the ADU size cap; an interactive mapping tool collected public comment through September 2025.
Apr 2026Virginia's statewide ADU law signed. Governor Abigail Spanberger signed SB 531 (Virginia Code § 15.2-2292.4), setting a statewide ADU floor for localities effective July 1, 2027 - but Richmond's own 2023 ordinance, adopted before the law's grandfather cutoff, keeps Richmond on its existing local rules rather than the new state minimums.
Aug 2026Code Refresh reaches a third draft. A revised draft was released mid-August 2026 for continued public review; a City Council vote, originally expected in spring 2026, had not yet taken place as of the most recent reporting.
Worth knowing: as of recent reporting, the city had issued building permits for roughly 117 ADUs since the 2023 ordinance took effect, with close to half from a single developer building small backyard cottages for tenants using housing vouchers - an early sign the by-right change is getting used, even before any Code Refresh changes take effect.
Permit process
How Richmond ADU permitting works
1
Confirm zoning & run the size math
Contact Zoning Administration to confirm your district's height/setback rules and calculate 1/3 of your home's floor area against the 500 sq ft floor.
2
Prepare your plans
You'll need a site plan showing property lines and all structures, plus a floor plan of the primary dwelling and the ADU showing permanent fixtures, egress, and square footage.
3
Submit through the online Permit Portal
Apply under the "Residential Building" category and select the correct work class (New or Light Alteration). A construction plan set and contractor are required if the project involves construction.
4
Plan review
The Bureau of Permits and Inspections targets an initial plan review within about 10 business days of a complete submission.
5
Trade permits & inspections
Pull separate trade permits for all electrical, plumbing, and mechanical work tied to the ADU, then schedule inspections.
6
Certificate of Occupancy
A detached ADU gets its own new address and a separate final CO. An attached ADU reclassifies the primary home as a Detached Two-Family Dwelling on a single CO.
Questions on zoning specifics go to PDRZoningAdministration@rva.gov or (804) 646-6340; permit and inspection questions go to PDRPermitsAndInspections@rva.gov or (804) 646-4169.
Budgeting
What it costs to build an ADU in Richmond
Garage conversion
Roughly $55,000-$150,000, the least expensive path since the shell already exists
Basement conversion
Roughly $85,000-$190,000, depending on existing ceiling height and utility access
New detached ADU
Roughly $120,000-$280,000+ for a code-compliant, freestanding unit; in practice, Richmond's size formula keeps many projects toward the smaller, less expensive end of this range unless the primary home is large
Permit fees
Vary by project scope and valuation - confirm current fees through the Bureau of Permits and Inspections before budgeting
These are general ranges from local contractor estimates and regional reporting, not quotes - actual cost depends heavily on lot conditions, finishes, and how much of the 1/3-of-home size allowance you can actually use. Richmond's construction market runs broadly comparable to Durham's.
Before you apply
Tips for a smooth approval
Run the size math before you design. Because the cap is 1/3 of your home's floor area or 500 sq ft, whichever is greater, a modest primary home can leave you well under 1,000 sq ft - confirm the exact number with Zoning before committing to a floor plan.
Check your specific zoning district's height and setback rules. Richmond doesn't set one citywide ADU height limit - it follows whatever your district already requires for accessory structures.
Plan for fire department access if building detached. The city requires access from the main street or a rear alley, which can constrain where a detached unit can sit on the lot.
Don't assume Code Refresh has taken effect. Richmond's broader zoning rewrite may eventually raise the ADU size cap, but as of this writing City Council hasn't voted on it - build to today's rules, not proposed ones.
Decide who's assigned to the permit early. An Owner Statement is only required if there's no construction, or no contractor assigned - assigning a licensed contractor up front can simplify the paperwork.
FAQ
Common questions
Do I need to live on the property to build an ADU in Richmond?
No. Richmond's own 2023 ordinance and its official permit guidance don't impose an owner-occupancy requirement.
Does Virginia have a statewide ADU law?
Yes, as of 2026. Senate Bill 531 (Virginia Code § 15.2-2292.4), signed April 13, 2026, requires all localities to permit ADUs in single-family zones by July 1, 2027 and caps permit fees at $500. Localities that already had their own ADU ordinance in place before January 1, 2026, including Richmond, are grandfathered and continue operating under their own local rules rather than the new state minimums.
How many ADUs can I build on one lot?
One ADU per lot, in addition to the primary single-family dwelling.
Do I need extra parking for an ADU?
No dedicated off-street parking space is required specifically for the ADU itself.
What's the maximum size for an ADU in Richmond?
One-third of the main dwelling's floor area, or 500 sq ft, whichever is greater. There's no flat citywide cap like 1,000 or 1,200 sq ft - the number scales with the size of your existing home.
Is Richmond changing its ADU rules soon?
Possibly. Richmond's "Code Refresh" zoning rewrite, implementing the 2020 Richmond 300 master plan, has proposed raising the ADU size allowance and easing duplex-plus-ADU development on more lots. A third draft was released in August 2026, but City Council had not yet voted as of the most recent reporting - the rules on this page are what currently applies.
How much does an ADU cost to build in Richmond?
Garage conversions tend to run roughly $55,000-$150,000, basement conversions $85,000-$190,000, and new detached units $120,000-$280,000 or more, based on local contractor estimates and regional reporting - though Richmond's size formula often keeps actual projects toward the smaller end unless the primary home is large.
How many ADUs has Richmond actually permitted?
Recent reporting put the total at roughly 117 building permits issued since the 2023 by-right ordinance took effect, with a large share coming from a single affordable-housing-focused developer building backyard cottages for voucher-holding tenants.
Can I rent my Richmond ADU out on Airbnb or a short-term rental platform?
Richmond regulates short-term rentals separately from its ADU ordinance, with its own permitting rules. Confirm current short-term rental requirements with the city before finalizing plans if that's part of your goal.
