We're still verifying Fairfax County, VA's answers against the county code.

I-3Light Intensity Industrial (I-3)

Fairfax County, VA · Fairfax County Zoning Ordinance

I-3 provides for scientific research, development and training, offices, light-intensity production of goods, and related supporting nonresidential activities -- a broad spectrum of clean industries under enhanced performance standards. Height 75ft. FAR 0.40 (up to 0.50 by Board). Front setback equal to building height (at least 40ft); side equal to height (none abutting a railroad). Landscaped open space min 15%. Min lot 40,000 sq ft. Section 2104.3.

Development standards in I-3

Front setback	At least the greater of the building height and 40 ft “[1] Refer to subsection 5108.5 for provisions that may qualify the setback requirements.” “Front setback, minimum Setback equal to building height; at least 40 feet”	2104
Side setback	At least 0 ft if the lot abuts a railroad right-of-way; otherwise at least the building height “[1] Refer to subsection 5108.5 for provisions that may qualify the setback requirements.” “Side setback, minimum Setback equal to building height; none required abutting railroad right-of-way”	2104
Side setback	Lot line abutting a railroad right-of-way: Not computed here: the ordinance makes it depend on facts about the site	2104
Rear setback	At least 0 ft if the lot abuts a railroad right-of-way; otherwise at least the building height “[1] Refer to subsection 5108.5 for provisions that may qualify the setback requirements.” “Rear setback, minimum Setback equal to building height; none required abutting railroad right-of-way”	2104
Rear setback	Lot line abutting a railroad right-of-way: Not computed here: the ordinance makes it depend on facts about the site	2104
Maximum height	At most 75 ft	2104
Maximum FAR	At most 0.4 “[4] An increase to 0.50 FAR may be permitted by the Board in accordance with subsection 5100.2.E(4).”	2104
Maximum FAR	Board-approved FAR increase: Not computed here: the ordinance makes it depend on facts about the site	2104
Minimum lot size	At least 40,000 sq ft “[2] Lot area and lot width may be modified in accordance with subsection 5100.2.K.”	2104
Minimum lot width	At least 100 ft “[2] Lot area and lot width may be modified in accordance with subsection 5100.2.K.”	2104
Minimum open space	At least 15% “[3] Open space is calculated in accordance with subsection 5100.3.A(3).” “Landscaped open space, minimum [3] 15 percent of gross area”	2104

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.

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 I-3

DependsLight Manufacturing Varies
Depends: by right, only if the use is a type or location that Sec. 4102.6.L(1) allows here and the use stays within the limits in Sec. 4102.6.L(3)
Table 4101.1 lists “Production or Processing” as P in the I-3 column. P = permitted by right; SE = special exception; SP = special permit; A = accessory only; AP = administrative permit (Table 4101.1).
ConditionalWarehouse / Distribution
Table 4101.1 lists “Warehouse” as SE in the I-3 column. P = permitted by right; SE = special exception; SP = special permit; A = accessory only; AP = administrative permit (Table 4101.1).
AllowedOffice / R&D
Table 4101.1 lists “Office” as P in the I-3 column. P = permitted by right; SE = special exception; SP = special permit; A = accessory only; AP = administrative permit (Table 4101.1).
Not AllowedSTR - Short-Term Rentals
Table 4101.1 has no entry for “Short-Term Lodging” in the I-3 column. The table's own legend: a blank cell indicates the use cannot be established in that zoning district (Table 4101.1).
Not AllowedResidential
Table 4101.1 has no entry for “Dwelling, Multifamily” in the I-3 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-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-4 R-5 R-8 R-A R-C R-E R-MHP