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R-4Residential (R-4), 4 DU/acre

Fairfax County, VA · Fairfax County Zoning Ordinance

R-4 permits single-family detached homes on medium-sized lots (conventional minimum 8,400 sq ft; Table 2102.9). Max 4 DU/acre. Single-family dwellings: height 35ft; other principal uses 60ft (Table 2102.9). Front setback 30ft, side 10ft, rear 25ft. Moderate-density suburban development common throughout Fairfax.

Development standards in R-4

Front setback	Single-family dwellings, conventional subdivision: At least 30 ft	2102
	Single-family dwellings, cluster subdivision: At least 20 ft	2102
	Other principal uses: At least 25 ft for a building up to 40 ft tall, 29 ft up to 45 ft, 32 ft up to 50 ft, 36 ft up to 55 ft, 39 ft up to 60 ft; no figure above that height	2102
Side setback	Single-family dwellings, conventional subdivision: At least 10 ft	2102
	Single-family dwellings, cluster subdivision: At least 8 ft	2102
	Other principal uses: At least 10 ft for a building up to 20 ft tall, 12 ft up to 25 ft, 15 ft up to 30 ft, 18 ft up to 35 ft, 21 ft up to 40 ft, 24 ft up to 45 ft, 27 ft up to 50 ft, 29 ft up to 55 ft, 32 ft up to 60 ft; no figure above that height	2102
Rear setback	Single-family dwellings: At least 25 ft	2102
Rear setback	Other principal uses: At least 25 ft for a building up to 45 ft tall, 27 ft up to 50 ft, 29 ft up to 55 ft, 32 ft up to 60 ft; no figure above that height	2102
Maximum height	Single-family dwellings: At most 35 ft	2102
Maximum height	Other principal uses: At most 60 ft	2102
Maximum FAR	Other principal uses, public uses: At most 0.35	2102
	Other principal uses, uses other than residential or public: At most 0.3	2102
	Single-family dwellings: No requirement	2102
Max density	Conventional subdivision: At most 4 dwellings per acre	2102
	Cluster subdivision, approved by the Director: At most 4 dwellings per acre	2102
	Cluster subdivision, approved by special exception: Not computed here: the ordinance makes it depend on facts about the site	2102
Minimum lot size	Conventional subdivision: At least 8,400 sq ft	2102
	Cluster subdivision, cluster lot not meeting the conditions of note [3]: At least 6,000 sq ft “[3] The minimum lot area of the cluster subdivision lot is 8,000 square feet and the minimum lot width of the cluster subdivision lot is 70 feet for interior lots and 95 feet for corner lots if any portion of a cluster subdivision lot is (a) located within 25 feet of the peripheral boundary of the cluster subdivision, (b) any portion of a contiguous lot located outside the cluster subdivision’s peripheral boundary is zoned to a district that permits a maximum density of four du/ac or less, and (c) the contiguous lot is vacant or contains a single-family detached dwelling, then this does not apply if the contiguous development is zoned to the PDH-4 District, or to the R-4 District and is developed or approved for a cluster subdivision.”	2102
	Cluster subdivision, cluster lot meeting the peripheral-boundary conditions of note [3]: At least 8,000 sq ft “[3] The minimum lot area of the cluster subdivision lot is 8,000 square feet and the minimum lot width of the cluster subdivision lot is 70 feet for interior lots and 95 feet for corner lots if any portion of a cluster subdivision lot is (a) located within 25 feet of the peripheral boundary of the cluster subdivision, (b) any portion of a contiguous lot located outside the cluster subdivision’s peripheral boundary is zoned to a district that permits a maximum density of four du/ac or less, and (c) the contiguous lot is vacant or contains a single-family detached dwelling, then this does not apply if the contiguous development is zoned to the PDH-4 District, or to the R-4 District and is developed or approved for a cluster subdivision.”	2102
	Conventional subdivision, average lot area: Not computed here: the ordinance makes it depend on facts about the site	2102
Minimum lot width	Conventional subdivision, interior lot: At least 70 ft “[4] Lot width may be modified in accordance with subsection 5100.2.K.”	2102
	Conventional subdivision, corner lot: At least 95 ft “[4] Lot width may be modified in accordance with subsection 5100.2.K.”	2102
	Cluster subdivision, interior lot, cluster lot meeting the peripheral-boundary conditions of note [3]: At least 70 ft “[4] Lot width may be modified in accordance with subsection 5100.2.K.” “[3] The minimum lot area of the cluster subdivision lot is 8,000 square feet and the minimum lot width of the cluster subdivision lot is 70 feet for interior lots and 95 feet for corner lots if any portion of a cluster subdivision lot is (a) located within 25 feet of the peripheral boundary of the cluster subdivision, (b) any portion of a contiguous lot located outside the cluster subdivision’s peripheral boundary is zoned to a district that permits a maximum density of four du/ac or less, and (c) the contiguous lot is vacant or contains a single-family detached dwelling, then this does not apply if the contiguous development is zoned to the PDH-4 District, or to the R-4 District and is developed or approved for a cluster subdivision.”	2102
	Cluster subdivision, corner lot, cluster lot not meeting the conditions of note [3]: At least 70 ft “[4] Lot width may be modified in accordance with subsection 5100.2.K.” “[3] The minimum lot area of the cluster subdivision lot is 8,000 square feet and the minimum lot width of the cluster subdivision lot is 70 feet for interior lots and 95 feet for corner lots if any portion of a cluster subdivision lot is (a) located within 25 feet of the peripheral boundary of the cluster subdivision, (b) any portion of a contiguous lot located outside the cluster subdivision’s peripheral boundary is zoned to a district that permits a maximum density of four du/ac or less, and (c) the contiguous lot is vacant or contains a single-family detached dwelling, then this does not apply if the contiguous development is zoned to the PDH-4 District, or to the R-4 District and is developed or approved for a cluster subdivision.”	2102
	Cluster subdivision, corner lot, cluster lot meeting the peripheral-boundary conditions of note [3]: At least 95 ft “[4] Lot width may be modified in accordance with subsection 5100.2.K.” “[3] The minimum lot area of the cluster subdivision lot is 8,000 square feet and the minimum lot width of the cluster subdivision lot is 70 feet for interior lots and 95 feet for corner lots if any portion of a cluster subdivision lot is (a) located within 25 feet of the peripheral boundary of the cluster subdivision, (b) any portion of a contiguous lot located outside the cluster subdivision’s peripheral boundary is zoned to a district that permits a maximum density of four du/ac or less, and (c) the contiguous lot is vacant or contains a single-family detached dwelling, then this does not apply if the contiguous development is zoned to the PDH-4 District, or to the R-4 District and is developed or approved for a cluster subdivision.”	2102
	Cluster subdivision, interior lot, cluster lot not meeting the conditions of note [3]: No requirement	2102
Minimum open space	Cluster subdivision: At least 25%	2102
Minimum open space	Conventional subdivision: No requirement	2102

Each row above is the ordinance’s own rule, written out in words and cited to its section. Where a figure depends on what you build (the kind of building, a conventional or cluster subdivision, an interior or corner lot, or the building’s height), each case is its own line; where it depends on the building height, the cited table says how that height is measured. An affordable dwelling unit development has its own table with different figures; see 2102.

Read from Fairfax County Zoning Ordinance, effective through 2026-07-01. We last checked with the publisher on 2026-09-14 and found nothing newer -- a check on that date, not a promise about today.

How complete is this market? Across 239,083 parcels we answer 96.1% of the 6 questions this site is built to answer, each with a source you can check. The rest are shown as “not recorded” rather than filled in — we would rather be short than wrong. A further 13,550 properties inside the county line are zoned by an incorporated town with its own ordinance, not by the county, so this county ordinance does not govern them and they are not counted above or below — which is why we publish this market as Fairfax County (excl. Vienna and Herndon). Look one of those up and we will tell you which town governs it.

Permitted uses in R-4

AllowedSingle-Family Residential
Table 4101.1 lists “Dwelling, Single-Family Detached” as P in the R-4 column. P = permitted by right; SE = special exception; SP = special permit; A = accessory only; AP = administrative permit (Table 4101.1).
DependsAccessory Dwelling Units Varies
Depends: administrative permit, only if the use is a type or location that Sec. 4102.7.B allows here and the use stays within the limits in Sec. 4102.7.B; special permit, only if the use is a type or location that Sec. 4102.7.B allows here and the use stays within the limits in Sec. 4102.7.B; this table cell allows the use in more than one way (administrative permit or special permit), and the use standards in Sec. 4102.7.B set which way applies
Table 4101.1 lists “Accessory Living Unit” as AP/SP in the R-4 column. P = permitted by right; SE = special exception; SP = special permit; A = accessory only; AP = administrative permit (Table 4101.1).
DependsHome Occupation Varies
Depends: administrative permit, only if the use is a type or location that Sec. 4102.7.H allows here and the use stays within the limits in Sec. 4102.7.H; special permit, only if the use is a type or location that Sec. 4102.7.H allows here and the use stays within the limits in Sec. 4102.7.H; this table cell allows the use in more than one way (administrative permit or special permit), and the use standards in Sec. 4102.7.H set which way applies
Table 4101.1 lists “Home-Based Business” as AP/SP in the R-4 column. P = permitted by right; SE = special exception; SP = special permit; A = accessory only; AP = administrative permit (Table 4101.1).
DependsSTR - Short-Term Rentals Varies
Depends: administrative permit, only if the use is a type or location that Sec. 4102.7.O allows here and the use stays within the limits in Sec. 4102.7.O
Table 4101.1 lists “Short-Term Lodging” as AP in the R-4 column. P = permitted by right; SE = special exception; SP = special permit; A = accessory only; AP = administrative permit (Table 4101.1). Fairfax defines this as a room or space intended for TRANSIENT OCCUPANCY for a charge, and expressly NOT a bed and breakfast, hotel, motel or accessory living unit (Article 9). It needs a short-term lodging permit from the Zoning Administrator, and the operator must be a permanent resident of the property (Sec. 4102.7.O).
Not AllowedCommercial / Retail
Table 4101.1 has no entry for “Retail Sales, General” in the R-4 column. The table's own legend: a blank cell indicates the use cannot be established in that zoning district (Table 4101.1).
Not AllowedMulti-Family Residential
Table 4101.1 has no entry for “Dwelling, Multifamily” in the R-4 column. The table's own legend: a blank cell indicates the use cannot be established in that zoning district (Table 4101.1).

"Conditional" means the use generally requires a public hearing or special-exception approval — a very different timeline and risk profile from a by-right permit.

This is the zone. What about the parcel?

Zone rules are the starting point — the answer for a specific property also depends on lot size, overlays, existing improvements and site conditions. Run a free address lookup to see what applies to one property.

Look up an address

Sources

Fairfax County Zoning Ordinance — read the ordinance
Fairfax County — official zoning map / authority
Standards as recorded by Zonescore: Fairfax County Zoning Ordinance (enCodePlus, current)

Values are read from the Fairfax County Zoning Ordinance.

Other Fairfax County zones

C-1 C-2 C-3 C-4 C-5 C-6 C-7 C-8 I-2 I-3 I-4 I-5 I-6 I-I PCC PDC PDH PDH-1 PDH-12 PDH-16 PDH-2 PDH-20 PDH-3 PDH-30 PDH-4 PDH-40 PDH-5 PDH-8 PRC PRM PTC R-1 R-12 R-16 R-2 R-20 R-3 R-30 R-5 R-8 R-A R-C R-E R-MHP