Shawsville

Montgomery County, Virginia (the New River Valley county — not Montgomery County, Maryland; Ohio; Pennsylvania; Tennessee; Kansas; Alabama; or any of the other 18 U.S. counties sharing the name) regulates accessory dwelling units through its county Zoning Ordinance, administered by the Montgomery County Department of Planning and GIS Services under the authority of the Montgomery County Board of Supervisors. Virginia is a Dillon Rule state (Commonwealth v. County Bd. of Arlington County, 217 Va. 558 (1977)); the General Assembly has not enacted any statewide ADU preemption, and Montgomery County's authority to regulate or permit second dwellings derives solely from the general zoning enabling statute at Va. Code § 15.2-2280 and the ordinance-content authorization at § 15.2-2286. Montgomery County has not adopted a standalone ministerial ADU ordinance of the California / Oregon / Washington type. Second-dwelling pathways on unincorporated parcels are: (a) 'family subdivision' or family-exemption/kinship dwelling under the zoning ordinance for a family-member occupant; (b) a Special Use Permit approved by the Board of Supervisors following Planning Commission recommendation, which is the typical path for a non-kin rental second dwelling; or (c) a minor subdivision to place the second dwelling on its own lot. The Town of Blacksburg (home to Virginia Tech) and the Town of Christiansburg (county seat) are incorporated towns within the county and have their own separate zoning ordinances that govern parcels within their respective town limits — this county ordinance does NOT apply inside those town limits. The Virginia Tech student-housing market creates unusually high rental demand in and around Blacksburg, making ADU-as-rental policy especially consequential, but the regulatory framework remains conventional Dillon-Rule Virginia zoning with discretionary SUP approval as the primary non-kin rental pathway.

• Montgomery County Code — Zoning Ordinance (Chapter 10 of the county code, as maintained on Municode)
• Montgomery County Department of Planning and GIS Services
• Montgomery County Board of Supervisors — adopting body for zoning ordinance amendments and Special Use Permits
• Montgomery County Planning Commission
• Va. Code § 15.2-2280 — general zoning enabling authority for Virginia localities
• Va. Code § 15.2-2286 — permissible contents of local zoning ordinances

State-floor overlay: Virginia has not enacted any statewide ADU preemption statute. Virginia is a Dillon Rule state: localities possess only those powers expressly granted by the General Assembly (Commonwealth v. County Bd. of Arlington County, 217 Va. 558 (1977); Board of Supervisors of James City County v. Rowe, 216 Va. 128 (1975)). The general zoning enabling statute at Va. Code § 15.2-2280 grants counties broad authority to regulate land use, and § 15.2-2286 enumerates the specific ordinance provisions that may be included. Neither statute, nor any section of Title 15.2 Chapter 22 Article 7, mandates that a locality permit ADUs, requires ministerial (non-discretionary) review of ADU applications, caps parking requirements, caps fees, voids owner-occupancy requirements, or otherwise preempts local ADU decision-making. ADU preemption bills have been introduced in the Virginia General Assembly in multiple recent sessions (HB 2046 in 2023; HB 900 and HB 1628 in 2024; related bills in 2025) without enactment of a statewide ADU-by-right preemption. Montgomery County is therefore free to permit, restrict, or prohibit second dwellings under its zoning ordinance, within the ordinary constitutional limits on land-use regulation and subject to the Virginia Fair Housing Law.

Montgomery County administers or is subject to several overlay regimes that materially affect ADU siting on unincorporated parcels: (1) FEMA National Flood Insurance Program Special Flood Hazard Areas along the New River, Little River, Tom's Creek, Stroubles Creek, Elliott Creek, North Fork of the Roanoke River, and various tributaries, administered through the county's floodplain ordinance; (2) steep-slope and karst-terrain considerations across much of the county, including significant sinkhole and carbonate-rock geology in the Appalachian Valley-and-Ridge province, which affect septic siting and foundation design (Virginia Department of Environmental Quality has karst-area guidance and the Virginia Department of Health applies specific septic standards in karst areas); (3) wildfire risk tracked by the Virginia Department of Forestry in the more heavily forested western and southern portions of the county adjacent to the Jefferson National Forest, with wildfire risk elevated in the Appalachian Mountain terrain — Virginia does not have a California-style Very High Fire Hazard Severity Zone regulatory overlay with mandatory ignition-resistant construction requirements, and the Virginia Uniform Statewide Building Code has not statewide-adopted the International Wildland-Urban Interface Code; (4) Agricultural and Forestal Districts (AFDs) established under Va. Code § 15.2-4300 et seq., which provide participating landowners use-value taxation and subdivision-deferral protections in exchange for a commitment to keep land in agricultural or forestal use — Montgomery County has established multiple AFDs over the decades, and an ADU on an AFD-enrolled parcel is generally permitted for agricultural-accessory uses but may conflict with AFD purposes if proposed as non-agricultural commercial rental; (5) Chesapeake Bay Preservation Act applicability — Montgomery County is NOT in the Tidewater area covered by the Chesapeake Bay Preservation Act (Va. Code § 62.1-44.15:67 et seq.), and the New River Basin drains to the Ohio/Mississippi system, not the Chesapeake Bay, so Resource Protection Areas (RPAs) and Resource Management Areas (RMAs) do not apply; (6) Virginia Tech property and federal lands — the Virginia Tech main campus and agricultural research facilities occupy significant land in and around Blacksburg, and the Jefferson National Forest (managed by the U.S. Forest Service) occupies substantial acreage in the western/southern county — federal and state lands are outside the scope of county zoning, but adjacency to these lands affects private-parcel development on neighboring properties; (7) New River scenic-river and Wild & Scenic corridor considerations in certain segments — the New River through Montgomery County is not federally designated Wild & Scenic, but recreational, scenic, and ecological values shape some local planning attention; (8) the county does not have a broad historic-district overlay covering large portions of the unincorporated county, though individual properties (such as Smithfield Plantation in Blacksburg) are listed on the Virginia Landmarks Register or National Register and receive those federal/state protections. The absence of a Chesapeake Bay overlay is a meaningful difference from eastern Virginia counties and simplifies some environmental-review steps.

• FEMA National Flood Insurance Program — Special Flood Hazard Areas (New River, Little River, Stroubles Creek, Tom's Creek, others) — Montgomery County participates in the National Flood Insurance Program and administers a county floodplain ordinance satisfying the NFIP minimum standards. Principal Special Flood Hazard Area (SFHA) extents in the county are along the New River (the county's largest river and a major through-flowing feature), Little River, Tom's Creek (through the Virginia Tech campus and south Blacksburg area), Stroubles Creek, Elliott Creek, and various tributaries. An ADU within an SFHA must comply with NFIP elevation requirements (lowest finished floor at or above Base Flood Elevation plus any county freeboard — Virginia's Uniform Statewide Building Code sets a baseline freeboard but counties may add more), flood vent requirements on enclosed areas below BFE, anchoring requirements, and post-construction Elevation Certificate filing. Owners should confirm the current-effective FIRM panel at the FEMA Map Service Center before design; FEMA periodically updates Virginia county maps. Lenders and the NFIP Write Your Own program will require flood insurance for mortgaged SFHA parcels.
• Karst and sinkhole terrain — septic and foundation implications — Substantial portions of Montgomery County lie within the Appalachian Valley-and-Ridge carbonate-rock belt, where sinkholes, disappearing streams, and subsurface drainage pathways are common. Karst terrain materially affects ADU siting in two ways: (a) the Virginia Department of Health applies enhanced setback and design standards for on-site sewage disposal systems (septic) in karst areas to protect groundwater, which can rule out some parcels for additional dwelling-unit septic capacity or require alternative (e.g., mound, pretreatment, or low-pressure-dose) septic designs at substantially higher cost; (b) foundation design for a detached ADU on karst terrain may require enhanced geotechnical investigation and design to address sinkhole risk, adding engineering cost. The Virginia Department of Environmental Quality publishes karst-area guidance and the Virginia Geological Survey publishes sinkhole-inventory maps; owners should consult these resources and their local health district at the pre-application stage.
• Virginia Agricultural and Forestal Districts (local option under state law) — Montgomery County has established Agricultural and Forestal Districts under the state AFD Act. Enrollment is voluntary; participating landowners commit to keeping land in agricultural or forestal use for a specified term (typically 4-10 years) in exchange for use-value assessment (Va. Code § 58.1-3230 et seq.) and limited protection from certain governmental actions that would disrupt agricultural use. An ADU on an AFD-enrolled parcel is generally permitted if it is an accessory use to continued agricultural operation (e.g., a farm-labor dwelling, family-kinship dwelling, or tenant farmer residence), but non-agricultural commercial-rental ADUs may conflict with AFD purposes and trigger AFD committee review or require withdrawal from the district with possible rollback-tax consequences. Owners should consult the Montgomery County AFD Advisory Committee and the zoning administrator before assuming ADU compatibility with an AFD-enrolled parcel.
• Virginia Department of Forestry wildfire risk and Virginia Statewide Building Code WUI provisions — Virginia has wildfire risk in the Appalachian and Blue Ridge counties, and Montgomery County's western and southern mountainous edge adjacent to the Jefferson National Forest has elevated wildfire exposure. Unlike California, Virginia does not have a statewide Very High Fire Hazard Severity Zone overlay that mandates WUI-rated construction materials on a per-parcel basis. The Virginia Department of Forestry publishes wildfire risk assessments and promotes defensible-space practices, but enforcement is advisory rather than regulatory. The Virginia Uniform Statewide Building Code, which is the single statewide building code (localities cannot impose more stringent building standards), does include Appendix K of the International Wildland-Urban Interface Code only where adopted; Virginia has not statewide-adopted the IWUIC. Owners in wildfire-exposed Montgomery County locations should follow best practices but face no locality-imposed WUI construction overlay analogous to California Chapter 7A.
• Jefferson National Forest adjacency — Substantial portions of western and southern Montgomery County lie adjacent to the Jefferson National Forest (administered together with the George Washington National Forest by the U.S. Forest Service as GWJNF). The Jefferson National Forest is federal land; federal regulation applies to activities within the forest boundary, not to private parcels outside it. However, private parcels abutting the national forest may face scenic, access, wildlife, and wildfire considerations, and individual deed restrictions, conservation easements, or access easements may apply to specific parcels. Owners of parcels adjacent to the forest should check the zoning district and any recorded easements, and contact the Eastern Divide or New Castle Ranger District for any question involving access, boundary, or adjacent-use coordination.
• Virginia Tech and related state-institution land — Virginia Tech's main campus in the Town of Blacksburg, together with its extensive agricultural research, experimental, and open-space land holdings in and around Blacksburg and elsewhere in Montgomery County, is state-owned land not subject to county zoning. The university's presence is the single largest economic and demographic driver in the county. The relevance for ADU purposes is indirect but material: (a) the Virginia Tech student population drives unusually high rental demand in Blacksburg and adjacent county areas, which makes ADU-as-rental economics attractive but also draws heightened political scrutiny of near-campus rental density; (b) university expansion over time can alter zoning and infrastructure conditions on adjoining private parcels; (c) the university is not itself a permitting authority for private-parcel ADUs, but its land-use decisions shape the county development environment. Private-parcel ADU projects on parcels adjacent to Virginia Tech land should consult the Town of Blacksburg (if inside town limits) or Montgomery County (if outside town limits) for the applicable zoning, and should not assume university proximity changes the permit process.
• Virginia Dam Safety program for dams upstream of developed areas (as applicable) — Montgomery County contains several regulated dams under the Virginia Dam Safety program; dam owners bear the primary compliance obligation, but downstream parcels within a regulated dam's inundation zone may face siting, notification, or insurance considerations for new dwelling construction. This is a less common constraint than floodplain or karst and applies only to specific downstream parcels. Owners should consult the DCR Dam Safety and Floodplain Management program and the county floodplain administrator for any parcel in a dam inundation zone.

The Montgomery County Department of Planning and GIS Services (for zoning and Special Use Permits) and the Montgomery County Department of Inspections (for building permits, electrical, plumbing, and mechanical) share permitting authority over ADU-style projects on unincorporated parcels within the county. The county is approximately 387 square miles in southwestern Virginia in the New River Valley, bordered by Floyd County to the south, Giles County to the west, Pulaski County to the southwest, Roanoke County to the east, and Craig and Roanoke counties to the northeast. The incorporated towns within Montgomery County are the Town of Blacksburg (home to Virginia Polytechnic Institute and State University — Virginia Tech), the Town of Christiansburg (county seat), and smaller incorporated communities; parcels within those town corporate limits are permitted by the towns, not the county. Unincorporated communities permitted by the county include Riner, Shawsville, Elliston, Pilot, Prices Fork, Lafayette, Long Shop, Ironto, and others. For an ADU-style project on an unincorporated parcel, the typical sequence is: (a) pre-application zoning consultation with the zoning administrator to confirm which pathway applies (by-right family exemption, discretionary SUP, or minor subdivision); (b) if an SUP is required, application to the Planning Commission and Board of Supervisors via the statutory public-hearing process; (c) site plan review if the parcel or zoning district requires it; (d) building permit application to the Department of Inspections; (e) well and septic evaluation by the Virginia Department of Health — New River Health District for parcels not served by public utilities; (f) construction inspections; (g) certificate of occupancy. Applicants should expect a materially longer timeline than a first-dwelling build if a Special Use Permit is required, because SUP is a public-hearing process subject to statutory notice under Va. Code § 15.2-2285.