Every base district organized by family — click any row to expand
The RSA family covers Philadelphia's rowhouse and semi-detached fabric — the defining residential form of the city's older neighborhoods. All RSA districts permit only single-family homes by right; multi-family use requires a variance in every sub-district. The differences across RSA-1 through RSA-6 are primarily lot size, required setbacks, and how urban vs. suburban the assumed context is. RSA-5 is by far the most common, covering the majority of the city's residential blocks; RSA-6 is the densest and shortest. RSA-1 through RSA-4 are transitional districts found in outer and middle neighborhoods.
All RSA sub-districts share a 38-foot maximum height (except RSA-6's 25-foot default), purely residential use permissions, and contextual front setback rules tied to neighboring buildings.
RSA-1 applies to the most suburban-feeling of Philadelphia's attached housing districts — blocks with wider lots, deeper front setbacks, and more open space than typical rowhouse streets. You'll find RSA-1 in parts of Roxborough, Mt. Airy, and some sections of the Northeast where the street pattern reflects early-twentieth-century residential development on the edge of the city. The 25-foot minimum front setback and 50-foot minimum lot width produce a noticeably different streetscape from the tight urban rows of RSA-5.
Only single-family homes are by right. Detached and semi-detached building types are permitted; fully attached rowhouses are generally not. RSA-1's large lot minimums mean it rarely appears in the kind of small-lot infill debates that dominate ZBA coverage.
RSA-2 steps down from RSA-1 — still single-family only, still focused on detached and semi-detached building types, but on somewhat smaller lots with a shorter required front setback. It appears in middle-ring neighborhoods where the housing stock mixes detached houses with semi-detached twins: parts of East Oak Lane, Logan, and similar areas. The 35-foot minimum lot width is still wide enough that attached rowhouses are uncommon.
Like RSA-1, RSA-2 is relatively unlikely to appear in ZBA variance hearings since the lot sizes give developers less to work with compared to the smaller-lot RSA-5 and RSA-6 districts.
RSA-3 marks the transition into the denser rowhouse form. With a 25-foot minimum lot width, fully attached rowhouses become common alongside semi-detached twins. Front setbacks shrink to 8 feet, producing a much more urban streetscape than RSA-1 or RSA-2. You'll find RSA-3 in neighborhoods like Germantown, Frankford, and parts of Kensington where attached housing predominates but lots are slightly larger than the RSA-5 minimum.
Still single-family only by right. The 50% lot coverage maximum is more permissive than RSA-1 or RSA-2, reflecting the more urban context. RSA-3 is close enough to RSA-5 in form that rezoning debates between the two occasionally arise.
RSA-4 is a relatively rare district designed for a specific Philadelphia building form: groups of attached rowhouses where no more than four units share a continuous run of buildings. Each group must have semi-detached buildings at both ends — meaning every RSA-4 "group" of attached homes is bookended by twins with side yards. This produces a distinct streetscape of alternating attached clusters and small gaps, found in some parts of North and West Philadelphia.
The 18-foot minimum lot width reflects the narrow Philadelphia rowhouse lot, but the group-of-four constraint prevents the long continuous rowhouse runs typical of RSA-5. End buildings in a group must have a minimum lot width of 30 feet and a 12-foot average side yard. Only single-family use is by right.
The RSD districts are Philadelphia's low-density, suburban-style zones — single-family detached houses on relatively large, private lots. They're common in Chestnut Hill, parts of the Northeast, and the city's edge neighborhoods. By-right development is limited to one detached house per lot. These districts rarely generate ZBA controversies because the large lot sizes make variances for additional density infrequent, but they come up in debates about Philadelphia's refusal to upzone lower-density neighborhoods.
All RSD sub-districts share a 38-foot height limit, detached-only building type, and no commercial uses by right. The differences are entirely in minimum lot size — RSD-1 is the most spacious, RSD-3 the most compact.
RSD-1 is the most restrictive residential district in the code — 10,000 square feet of lot area required, 75-foot lot width minimum, 35-foot front setback, and only 35% lot coverage allowed. This produces large, well-separated houses on generous lots. You'll find RSD-1 in the most suburban pockets of Philadelphia: parts of Chestnut Hill, Springfield Township edge, some sections of the Far Northeast. In a dense American city, RSD-1 parcels are unusual enough that most Philadelphians don't realize they're still within city limits.
RSD-2 is a step below RSD-1 in lot size but otherwise similar in character: detached single-family houses, 35-foot front setbacks, no commercial uses. Found in neighborhoods like Overbrook, parts of Germantown, and middle-ring sections of the Northwest where the housing stock transitions from suburban to urban. The smaller lots allow for more development than RSD-1 but still produce distinctly suburban streetscapes compared to rowhouse Philadelphia.
RSD-3 is the most urban-feeling of the detached districts, with a shorter 25-foot front setback and smaller minimum lot. It appears in transitional neighborhoods where detached houses sit alongside attached housing, and in areas where the lot fabric is finer-grained than the outer suburbs. The slightly reduced front setback produces a modest street presence closer to the RSA family. Still single-family detached only, no commercial, no multi-family.
RTA-1 is the only district in the code expressly designed for the semi-detached "twin" house — two dwelling units by right on a single lot. It's relatively rare; Philadelphia never mapped it broadly, preferring to handle duplexes through the RSA family with variances. Where you see RTA-1, expect blocks of paired twins, often in middle-ring neighborhoods where this building type was historically the norm. The existence of RTA-1 as a separate district is a useful reminder that the code does contemplate two-family housing as a baseline use — something advocates invoke when arguing for broader "missing middle" allowances.
RTA-1 is designed for the classic Philadelphia "twin" — two attached houses that share one wall, each on its own lot, functioning as a pair. Both a single-family unit and a two-family unit are by right; multi-family (three or more units) requires a variance. Dimensional standards are similar to RSA-3: 25-foot minimum lot width, 2,250 square foot minimum lot area, 8-foot front setback, 38-foot maximum height. Detached and semi-detached building types are permitted; fully attached rowhouses generally are not.
In neighborhoods dominated by RSA-5, an RTA-1 designation is meaningful — it's one of the few places where a property owner can add a second unit without ZBA approval. This makes RTA-1 parcels of particular interest to small-scale investors and "house-hacker" buyers. It's also a district housing advocates sometimes point to when arguing the city has already demonstrated it can map two-family housing without neighborhood collapse.
The RMX districts are planned-development zones — large parcels or assembled sites where a developer proposes a master plan that mixes residential with retail, office, or civic uses. Unlike most districts, RMX applies to an entire site rather than individual lots: RMX-1 requires a minimum 2-acre project area, RMX-2 requires 1 acre. RMX-3 has no minimum but is still designed for planned mid-rise development. You'll encounter RMX in stories about large planned communities, university-adjacent housing, and riverfront redevelopment — essentially any development big enough to propose its own internal street and open space layout.
All uses in RMX that go beyond housing require the commercial component to be part of a master plan approved by the Planning Commission. FAR in RMX-1 and RMX-2 is measured as a percentage of the total district (site) area, not individual lot area — a distinction that matters for density calculations.
RMX-1 is for large-scale planned residential communities at relatively modest density — think planned townhouse developments, small mixed-use campuses, or institutional housing projects. The 50% maximum occupied area (75% if historically significant structures are retained) produces an open, park-like site plan with significant green space. FAR is 150% of the total district area. All housing types (single, two, and multi-family) are by right within the approved master plan. Commercial uses are permitted only as part of the master plan and must be oriented to serve the development and its immediate surroundings.
RMX-2 steps up to 250% FAR and allows a more urban site coverage (75% of district area, including open-air parking). The smaller minimum district size (1 acre vs. 2 acres for RMX-1) and higher FAR make RMX-2 suitable for mid-rise planned communities in more urban contexts — infill development on assembled sites, adaptive reuse of large institutional properties, or mixed-income housing projects that benefit from master plan approval. Commercial uses are more broadly available to residents of the development and surrounding neighborhood.
RMX-3 is essentially the residential equivalent of CMX-3 in terms of density: 500% FAR, up to 100% lot coverage for non-residential or taller buildings. Unlike RMX-1 and RMX-2, there's no minimum district size, so RMX-3 can be applied to individual parcels rather than just assembled sites. It permits the broadest range of commercial uses within the residential family, including retail, office, restaurants, and visitor accommodations. You'll encounter RMX-3 in discussions of dense transit-adjacent housing and urban infill where the residential designation is preferred over a CMX designation.
The CA districts are Philadelphia's strip-mall and shopping-center zones — commercial areas designed around car access rather than pedestrian streets. No residential use is permitted. Surface parking lots and drive-throughs that are prohibited or restricted everywhere else in the CMX family are allowed here. CA districts are common along arterial roads like Roosevelt Boulevard, Aramingo Avenue, and sections of Bustleton Avenue where post-war commercial development followed car-dependent patterns.
CA zoning is increasingly contested — advocates argue that CA-mapped parcels along transit-accessible corridors represent missed opportunities for housing and walkable mixed-use development, and periodic remapping fights arise when property owners seek upzoning to CMX or IRMX.
CA-1 covers smaller auto-oriented commercial uses — gas stations, fast food, strip retail, small shopping centers. The 60% lot coverage limit and 5-foot side and rear yards (if used) still leave room for parking in front of or beside buildings. Surface and structured parking lots both require special exception approval, which means even parking lots need ZBA sign-off in CA-1 (a distinction from CA-2). A broad range of retail and commercial service uses are by right, but residential is entirely excluded.
CA-1 is distinct from CMX districts in one important respect: it explicitly anticipates and accommodates car-oriented uses like vehicle fueling stations (by special exception), commercial vehicle sales, and drive-throughs that are prohibited in most CMX districts.
CA-2 is designed for large shopping centers and big-box retail — uses that require substantial land area, extensive parking, and regional vehicle access. The 80,000 square foot minimum district size means CA-2 cannot be applied to individual small parcels; it's for significant commercial land assemblages. Unlike CA-1, CA-2 allows 100% lot coverage and has no side or rear yard requirements, enabling large footprint buildings surrounded by surface parking.
CA-2's use permissions are also broader than CA-1: hospitals, educational facilities, vehicle sales and rentals, and wholesale distribution are all by right. Surface and structured parking are by right (not special exception). In Philadelphia, CA-2 appears primarily in the Northeast along Roosevelt Boulevard and near the stadiums complex in South Philadelphia.
ICMX sits between the commercial and industrial worlds — it allows a full range of commercial uses alongside light and limited industrial uses, but prohibits residential. Think auto repair shops, wholesale distributors, warehouses, light manufacturing, and commercial services on the same block. It's applied to corridors and nodes that function as working commercial-industrial areas rather than either pure neighborhood retail or pure factory zones.
ICMX's 500% FAR and 60-foot height limit enable substantial building mass, while 100% lot coverage means no open space is required — typical of industrial contexts where the entire lot is productively used. Setbacks are only required where the lot abuts a residential district, in which case the more restrictive residential setback standards apply. Commercial uses are broadly permitted; limited industrial (but not general, intensive, or heavy industrial) is by right; wholesale and warehouse uses are by right.
The critical distinction from IRMX: no residential use. Caretaker quarters (a small on-site residential unit for a building manager) are the only housing-related use allowed. This makes ICMX a more commercially and industrially protective zone than IRMX, which allows full multi-family housing. ICMX is sometimes used as a buffer between residential neighborhoods and heavier industrial areas.
I-P is a specialized district for marine-related industrial uses along Philadelphia's waterfront — docks, wharves, piers, transit sheds, and the infrastructure that supports port operations. It's mapped along the Delaware River where the Philadelphia port complex operates. No residential use is permitted; commercial use is minimal. I-P comes up primarily in coverage of port development, industrial waterfront policy, and debates about waterfront access and land use along the Delaware.
I-P has no maximum FAR and no height limit in the base district (60-foot limit applies only where it abuts a residential or parks district). Lot coverage is 100%. The use table is narrow and purposeful: marine-related industrial uses (wharves, docks, piers, transit sheds, marine cargo handling) are the primary permitted uses. Heavy industrial uses including extractive industries and general industrial uses are permitted. Vehicle fueling is by right, as are warehouses, cargo storage, and trucking terminals — all supporting port operations. Commercial services are largely excluded.
I-P is not subject to the same FAR bonus system as CMX or IRMX districts. It has no mixed-income housing bonus because residential use is prohibited. The district is relevant primarily for stories about Philadelphia's port expansion, waterfront industrial land preservation, and the tension between port operations and public waterfront access.
Special Purpose districts work differently from every other zoning category in the code. Rather than applying a fixed set of dimensional standards to any parcel that falls within the district, SP districts are organized around an approved master plan specific to a named institution, campus, or facility. The master plan — not the code's dimensional tables — governs what gets built, where it goes, how tall it can be, and what uses are allowed.
The practical implication is significant: there is no single "SP-INS height limit" the way there is a CMX-3 height limit. Instead, Penn Medicine's master plan governs Penn Medicine's SP-INS parcels; Jefferson's master plan governs Jefferson's. Two hospitals a block apart in SP-INS can have entirely different allowable envelopes depending on what their respective master plans say. This is why SP districts are opaque to outside observers — the governing document is a plan approval, not a code provision.
Master plans in SP districts must be approved by the Philadelphia City Planning Commission and are typically reviewed every five years or triggered by a proposed amendment. Significant expansions, new building types, or changes in use require a master plan amendment — which goes back to the Planning Commission and is subject to public comment. This process is the primary civic lever for influencing what large institutions build. Unlike a ZBA variance, master plan amendments are reviewed by the Planning Commission and are subject to City Council approval in some cases.
For journalists: when covering a hospital expansion, university dormitory, or stadium project, the first question is whether it falls within the existing approved master plan envelope. If it does, it can proceed by right under that plan. If it exceeds the plan, an amendment is required — and that's when public process kicks in.
SP-INS is mapped around Philadelphia's major institutional campuses: Penn, Drexel, Jefferson, Temple, Penn Medicine, CHOP, Einstein, and dozens of smaller colleges, hospitals, and large nonprofit facilities. It's the most frequently encountered SP district in development coverage. The district is designed to allow institutions to grow and adapt over time under a long-range plan, rather than requiring a variance every time a building is proposed.
Uses permitted under SP-INS are broadly institutional — academic buildings, medical facilities, student housing, research labs, ancillary retail and services for the campus community. Housing for the general public is not a standard SP-INS use; if an institution wants to develop market-rate apartments on its campus, it typically needs a different zoning designation or a specific master plan carve-out. The master plan specifies building envelopes, height limits, setbacks, and phasing — all of which can vary building by building within the same campus.
SP-INS is where Philadelphia's most politically charged land use fights often happen: university encroachment into adjacent residential neighborhoods, hospital expansion across community streets, and debates about whether large tax-exempt institutions are serving or displacing the communities around them.
SP-CIV covers publicly owned or publicly serving civic facilities — government buildings, libraries, courthouses, cultural institutions, and similar uses that serve a broad public function. Unlike SP-INS, which is focused on the operational needs of private institutions, SP-CIV is oriented toward preservation and development of facilities that are fundamentally civic in character. The key distinction in the code: SP-CIV allows a "customary and complementary mix of uses" around the core civic function, giving somewhat more flexibility for ancillary retail, food service, and programming than the more tightly defined SP-INS. Development still requires an approved master plan.
SP-ENT is designed for large entertainment facilities — arenas, amphitheaters, convention centers, and similar major-draw venues — where the scale and traffic generation of the use requires site-specific planning rather than standard dimensional rules. Development of major entertainment facilities in accordance with an approved master plan is the code's stated intent. Associated large-capacity parking is also addressed within the master plan framework. In practice, SP-ENT is rare; most of Philadelphia's major venues are either in the sports stadium complex (SP-STA) or in a CMX district.
SP-STA is essentially a one-location district, mapped around the sports complex in South Philadelphia. It accommodates large-scale sporting facilities and the associated massive surface and structured parking that those facilities generate. Residential uses are prohibited; the district exists to serve the stadiums and their attendees. SP-STA is directly relevant to any coverage of stadium development, potential relocation of teams, or proposals to redevelop the surrounding parking lots — changes to the sports complex's footprint or use require master plan amendments subject to Planning Commission review.
SP-PO covers Fairmount Park, Wissahickon Valley Park, Pennypack Park, and other major public open spaces set aside for park and recreation use. Its purpose is explicitly preservationist — to protect lands from development rather than to enable it. Active and passive recreation uses are by right; most structures and built uses require special exception or master plan approval. SP-PO is relevant to stories about park stewardship, lease arrangements for park facilities, and occasional controversies over proposed development within park boundaries. The /SP-PO designation is also referenced in the industrial districts as a trigger for the 60-foot height limit when industrial uses abut it.
SP-AIR covers Philadelphia International Airport and the land immediately surrounding it. The district allows airport operations and a complementary mix of uses — cargo facilities, aircraft maintenance, ground transportation infrastructure, hotels, and ancillary retail serving travelers — while managing impacts on surrounding residential areas through the master plan framework. SP-AIR interacts with the /AHC (Airport Hazard Control) and /HHC (Heliport Hazard Control) overlay districts, which restrict building heights and certain uses within flight path corridors extending well beyond the airport's SP-AIR boundary.