Ampthill

Chesterfield County's zoning ordinance, comprehensively rewritten as the Zoning Ordinance Modernization (ZOMod) project and effective January 1, 2026, replaces a 1970s-era code. Accessory Dwelling Units (the ordinance's term; historically called 'in-law suites' or 'accessory apartments') are addressed at Section 19.2-32-15 (Dwelling, Accessory). The ZOMod update retained the conditional-use-permit (CUP) pathway for ADUs that do not meet the ordinance's recommended conditions, while reducing the application fee for ADUs meeting the recommended conditions from $300 to $100. Under the March 2024 staff-proposed framework that informed ZOMod, ADUs are permitted on lots of 12,000 square feet or larger with a size cap of the greater of 800 square feet or 40% of the primary dwelling's finished floor area, one additional off-street parking space, and occupancy restricted to family members of the primary-dwelling occupants (rental to non-family members is prohibited). Both attached (e.g., basement apartment) and detached ADUs are allowed; to qualify as an ADU rather than a mere accessory structure, the unit must include a separate living space, sleeping area, bathroom, and full kitchen. Chesterfield's approach is meaningfully more restrictive than California's ministerial ADU regime — owner-occupancy / family-use is required, the CUP process remains the default pathway for ADUs not meeting all recommended conditions (with reduced public-hearing burden under ZOMod but not eliminated), and the 12,000 sqft lot minimum excludes many denser residential subdivisions.

• Chesterfield County Zoning Ordinance (Chapter 19.2), Zoning Ordinance Modernization (ZOMod), effective January 1, 2026
• Chesterfield County Code, Chapter 19.2, Section 19.2-32-15 (Dwelling, Accessory)
• Chesterfield County Board of Supervisors ADU reform proposal (work session, March 21, 2024)
• Chesterfield County presentation to the Virginia Housing Commission ADU Workgroup, May 20, 2024

State-floor overlay: Virginia is a Dillon Rule state: Chesterfield County's land-use authority is a delegated power from the General Assembly. The principal enabling statutes are Va. Code Section 15.2-2280 (general zoning power to classify districts, regulate size/use of structures, minimum lot areas, setbacks, parking) and Va. Code Section 15.2-2286 (procedural zoning powers including conditional use permits and administrative variances). The ADU-specific state floor is Va. Code Section 15.2-2291, which requires every Virginia locality to permit accessory apartments in single-family residential districts subject to 'reasonable conditions' the locality may impose on size, design, and use. Virginia has NOT enacted a preemptive statewide ADU ministerial-approval framework of the California / Oregon / Washington type; Chesterfield's requirement for family occupancy, 12,000 sqft minimum lot, and CUP-adjacent process would be preempted in those states but is lawful in Virginia so long as the conditions are 'reasonable' under Section 15.2-2291. The Virginia Housing Commission ADU Workgroup (active 2023-2025) studied whether to propose a preemptive state ADU law but as of the 2026 session no such bill has been enacted.

Chesterfield County administers several county- and state-level overlay regimes that materially affect ADU siting: (1) the Chesapeake Bay Preservation Act (CBPA) Resource Protection Area (RPA) 100-foot riparian buffer, mandated by Va. Code Section 62.1-44.15:67 et seq. and administered locally by Chesterfield through the zoning and subdivision ordinances — RPA buffers protect all tidal and perennial non-tidal waters in the county and prohibit most new impervious surface within the 100-foot buffer; (2) the Flood Plain Management Ordinance (FEMA NFIP participant since March 1983, ordinance first adopted February 23, 1983) covering FEMA Special Flood Hazard Areas (SFHA) along the James River, Appomattox River, Swift Creek, Falling Creek, Proctors Creek, Pocoshock Creek, and numerous smaller tributaries, with the February 2024 effective FIRM panels providing the current regulatory floodplain map; (3) the Resource Management Area (RMA) buffer — the wider 'second-tier' CBPA buffer applied county-wide to 'intensely developed areas' as a Chesapeake Bay water-quality overlay; (4) airport noise and safety zones around the Richmond Executive-Chesterfield County Airport (FCI) and the broader Richmond International Airport (RIC, just across the James River in Henrico County, with its approach corridors crossing into northern Chesterfield); (5) airport noise and safety overlays around Defense Supply Center Richmond (DSCR) / Fort Lee airspace in the eastern county. Coastal Commission jurisdiction does NOT apply (Virginia has no California-style Coastal Commission; the CBPA is the functional analog). Very High Fire Hazard Severity Zones are NOT a Virginia regulatory category — Chesterfield has no WUI overlay comparable to California's CAL FIRE VHFHSZ system, though wildland fire risk exists in the rural Matoaca district. Historic districts in Chesterfield are locally designated; the notable ones are Historic Chesterfield Courthouse (around the 1749 courthouse complex) and several National Register properties.

• Chesapeake Bay Preservation Act Resource Protection Area (RPA) — 100-foot buffer — ADU designs that cantilever over, or place impervious surface within, the 100-foot RPA buffer require an RPA Exception, which involves a Water Quality Impact Assessment, staff review, and Planning Commission public hearing. Adding roughly 30-60 days to the overall ADU timeline for an RPA Exception is typical. Owners with creek-adjacent parcels along Swift Creek, Falling Creek, or Proctors Creek should confirm RPA status via the county parcel viewer before design.
• Chesterfield County Flood Plain Management Ordinance — FEMA NFIP participant — ADUs in an SFHA must have lowest floor elevated to or above Base Flood Elevation plus Chesterfield's freeboard, flood vents on any enclosed area below BFE, structural anchoring, and a post-construction Elevation Certificate. The substantial-improvement trigger (>50% of structure value) means a garage conversion or attached-unit addition to an existing flood-prone structure can cascade into full-structure floodplain compliance. Owners along Swift Creek, Falling Creek, the James, and the Appomattox should verify current FIRM status (2024 effective panels) before ADU design. Flood insurance is federally required for SFHA parcels with federally-backed mortgages.
• Airport noise and safety zones — Richmond Executive-Chesterfield County Airport (FCI) and Richmond International Airport (RIC) approach corridors — ADU siting inside the FCI Airport Overlay District is subject to height limits (typically 35 feet or the district base height, whichever is lower, within the approach / departure surfaces), noise attenuation considerations for DNL 65+ dB areas, and avigation easement recording for new residential parcels. The overlay does not prohibit ADUs but does constrain detached two-story ADU designs in the approach corridors. Owners in southern Matoaca and around FCI should verify Airport Overlay status before a two-story detached ADU design.
• Historic Chesterfield Courthouse area and locally-designated historic overlay districts — An ADU on a parcel within a locally-designated historic overlay district requires design review — typically staff review for minor additions, with Historic Preservation Committee review for more substantial proposals. Parcels that are individually National Register-listed but not in a local overlay are not subject to local design review for ADU additions (the National Register is informational / tax-credit-eligibility, not regulatory). Owners near the Courthouse complex should confirm overlay status before ADU design.

Because Chesterfield County contains no incorporated towns or cities, the entire county's ~437 square miles of land area is 'unincorporated' for permitting purposes and the Chesterfield County Planning Department and Building Inspection office are the single point of contact for every residential ADU permit in the county. ADU permits follow a two-track process under the post-ZOMod 2026 ordinance: (a) an accessory dwelling that meets all the recommended conditions in Section 19.2-32-15 (12,000 sqft lot, size cap, family occupancy, parking, setbacks, design) goes through a streamlined administrative path with a $100 application fee and public notification rather than a full CUP hearing cycle; (b) an ADU that deviates from any recommended condition requires a full Conditional Use Permit, which involves Planning Department case-manager review, pre-application meeting, Technical Review Committee, a community meeting if the district commissioner requires one, a Planning Commission public hearing, and a Board of Supervisors public hearing. CUP processing typically takes four to six months. All ADUs, regardless of approval pathway, require building permits through Building Inspection and trade permits (electrical, plumbing, mechanical), and parcels not served by public water and sewer (common in rural Matoaca and southern Chesterfield) must demonstrate adequate septic capacity through the Virginia Department of Health / Chesterfield County Health Department.