Overview
Code type
hybrid-pd
Naming convention
letter-code
Comprehensive 2020-02-26 rewrite (DRAFT 5.0 → adopted) replaced legacy Euclidean code with form-based-leaning hybrid: residential and commercial districts use 'Form Standards' tables (Table 4.1 LDR, Table 4.2 MDR, Table 4.3 Commercial Center). Sub-district granularity is high — LDR1-4, MDR1-3, BMV1-4, BMMD1-3, IC1-3, IE1-3, IH1-3, CAD-RCA/BCR/BV. Roof-pitch-conditional height bonus is a distinctive form-based mechanism.
Worth knowing
- Comprehensive 2020-02-26 zoning code rewrite — replaced legacy Euclidean code with form-based-leaning hybrid. Form Standards tables (4.1 LDR, 4.2 MDR, 4.3 Commercial Center) define dimensional rules; sub-district granularity is high (LDR1-4, MDR1-3, BMV1-4, BMMD1-3, IC1-3, IE1-3, IH1-3, CAD-RCA/BCR/BV). Recent rewrite means legacy aggregator data and pre-2020 underwriting analyses are stale. [severity: high; citation: lowermerion.org Building & Planning — 'New Zoning Code Adopted 02/26/2020']
- Roof-pitch-conditional height bonus in LDR districts: low-sloped roofs limited to 2 stories / 28 ft, but steep-sloped roofs (pitch >5:12 up to 12:12) permitted to 3 stories / 35 ft. Mechanism rewards pitched roofs aesthetically associated with the Main Line traditional architecture vocabulary; pro forma must value pitched-roof framing-cost premium as a height-bonus enabler, not just an aesthetic choice. [severity: high; citation: §155 LDR Form Standards (ecode360.com/35686330)]
- MDR3 transitional step-back rule: when adjacent to LDR / MDR1 / MDR2, MDR3 may rise from baseline 35 ft (2.5 stories) to 50 ft (4 stories) only with a 15-ft front step-back at the 3rd floor or 40 ft height. This is a contextual height taper — not a flat allowance. Massing studies must place transitional units carefully or the bonus disappears. [severity: high; citation: §155 MDR Form Standards]
+ 6 more in Quirks & notes
Districts
spec 14mu 8res_sf 4com 4res_mf 2res_th 1ind 1
| Code | Name | Category | Min lot | Height | Coverage | FAR | Du/ac | Parking | Setbacks F/S/R |
|---|---|---|---|---|---|---|---|---|---|
| LDR1 | Low Density Residential 1 | res_sf | — | [{'variant': 'low_slope_roof', 'value': 28, 'citation': '§155 LDR Form Standards — 2 stories / 28 ft for buildings with low-sloped roof'}, {'variant': 'steep_slope_roof_>5:12', 'value': 35, 'citation': '§155 LDR Form Standards — 3 stories / 35 ft for buildings with roof pitch >5:12 up to 12:12'}] ft[1] | — | — | — | — | — / — / — |
| LDR2 | Low Density Residential 2 | res_sf | — | [{'variant': 'low_slope_roof', 'value': 28}, {'variant': 'steep_slope_roof_>5:12', 'value': 35}] ft[2] | — | — | — | — | — / — / — |
| LDR3 | Low Density Residential 3 | res_sf | — | [{'variant': 'low_slope_roof', 'value': 28}, {'variant': 'steep_slope_roof_>5:12', 'value': 35}] ft[3] | — | — | — | — | — / — / — |
| LDR4 | Low Density Residential 4 | res_sf | — | [{'variant': 'low_slope_roof', 'value': 28}, {'variant': 'steep_slope_roof_>5:12', 'value': 35}] ft[4] | — | — | — | — | — / — / — |
| MDR1 | Medium Density Residential 1 | res_th | — | 35 ft[5] | — | — | — | — | — / — / — |
| MDR2 | Medium Density Residential 2 | res_mf | — | 35 ft[6] | — | — | — | — | — / — / — |
| MDR3 | Medium Density Residential 3 | res_mf | — | [{'variant': 'general', 'value': 35, 'citation': '§155 MDR Form Standards — 2.5 stories / 35 ft baseline'}, {'variant': 'transitional_to_LDR_or_lower_MDR', 'value': 50, 'citation': '§155 MDR Form Standards — 4 stories / 50 ft permitted with 15 ft front step-back at 3rd floor or 40 ft height when adjacent to LDR / MDR1 / MDR2'}] ft[7] | — | — | — | — | — / — / — |
| NC | Neighborhood Commercial | com | — | — | — | — | — | — | — / — / — |
| VC | Village Commercial | com | — | — | — | — | — | — | — / — / — |
| TC1 | Town Commercial 1 | com | — | — | — | — | — | — | — / — / — |
| TC2 | Town Commercial 2 | com | — | — | — | — | — | — | — / — / — |
| RHR | Rock Hill Road District | mu | — | — | — | — | — | — | — / — / — |
| BMV1 | Bryn Mawr Village 1 | mu | — | — | — | — | — | — | — / — / — |
| BMV2 | Bryn Mawr Village 2 | mu | — | — | — | — | — | — | — / — / — |
| BMV3 | Bryn Mawr Village 3 | mu | — | — | — | — | — | — | — / — / — |
| BMV4 | Bryn Mawr Village 4 | mu | — | — | — | — | — | — | — / — / — |
| BMMD1 | Bryn Mawr Medical District 1 | spec | — | — | — | — | — | — | — / — / — |
| BMMD2 | Bryn Mawr Medical District 2 | spec | — | — | — | — | — | — | — / — / — |
| BMMD3 | Bryn Mawr Medical District 3 | spec | — | — | — | — | — | — | — / — / — |
| MC | Medical Center District | spec | — | — | — | — | — | — | — / — / — |
| CAD-RCA | City Avenue District — Regional Center Area | mu | — | — | — | — | — | — | — / — / — |
| CAD-BCR | City Avenue District — Bala Cynwyd Retail | mu | — | — | — | — | — | — | — / — / — |
| CAD-BV | City Avenue District — Bala Village | mu | — | — | — | — | — | — | — / — / — |
| IN | Institutional | spec | — | — | — | — | — | — | — / — / — |
| IC1 | Institutional Civic 1 | spec | — | — | — | — | — | — | — / — / — |
| IC2 | Institutional Civic 2 | spec | — | — | — | — | — | — | — / — / — |
| IC3 | Institutional Civic 3 | spec | — | — | — | — | — | — | — / — / — |
| IE1 | Institutional Education 1 | spec | — | — | — | — | — | — | — / — / — |
| IE2 | Institutional Education 2 | spec | — | — | — | — | — | — | — / — / — |
| IE3 | Institutional Education 3 | spec | — | — | — | — | — | — | — / — / — |
| IH1 | Institutional Health 1 | spec | — | — | — | — | — | — | — / — / — |
| IH2 | Institutional Health 2 | spec | — | — | — | — | — | — | — / — / — |
| IH3 | Institutional Health 3 | spec | — | — | — | — | — | — | — / — / — |
| LI | Light Industrial | ind | — | — | — | — | — | — | — / — / — |
Confidence: confirmed partial under review not found
Overlays
FP-O
Floodplain Overlay District
FPAreas subject to base flood per Lower Merion Township Floodplain Overlay District Map; based on FEMA Flood Insurance Study dated March 2, 2016 or most recent revision
| items | Permitted uses limited to: cultivated/forested/grazing areas per soil conservation practices; outdoor plant nurseries / orchards per soil conservation practices; wildlife sanctuary, woodland preserve or arboretum; forestry / lumbering / reforestation per natural resources conservation practices; Restrictions on fill, excavation, structures; Floodproofing / elevation requirements per FEMA NFIP standards |
|---|
SS-O
Steep Slopes Overlay District
HSAreas with steep slopes per Township Steep Slopes Overlay map
| items | Limits earthwork, grading, and removal of stabilizing vegetation on steep slopes; Site plans must delineate slope thresholds |
|---|
WL-O
Wooded Lot Overlay District
ENVLots designated on Wooded Lot Overlay map; preserves tree-canopy character of mature suburban Main Line lots
| items | Limits removal of significant trees on wooded lots; May require tree-replacement or canopy-preservation plans for development |
|---|
OSP-O
Open Space Preservation Overlay District
CONLots designated on Open Space Preservation Overlay map
| items | Restricts development on designated open-space-preservation parcels; Cluster-development alternatives may be available to preserve open space in exchange for density transfer |
|---|
HR-O
Historic Resource Overlay District
HPProperties designated as Class 1 or Class 2 historic resources on Township Historic Resource Inventory; covers significant Main Line historic estates and commercial buildings
| items | Demolition review for Class 1 historic resources; Design review for additions / alterations to designated historic structures; Tax-incentive eligibility for preservation work |
|---|
State preemptions
PA Municipalities Planning Code (53 P.S. §10101 et seq.)applies
Qualifying condition
Lower Merion is a 1st-class township under PA state statutes (governed by 14 commissioners elected by ward); not 1st-class city (Philadelphia), not 2nd-class city (Pittsburgh), not 2nd-class A city (Scranton). Both 1st-class and 2nd-class townships are MPC-governed. MPC procedural framework applies in full.
Effect
MPC procedural framework binds zoning amendments, hearing-board procedure, curative-amendment / validity-challenge rights
PA MPC §503(1.1) — manufactured housing parityapplies
Qualifying condition
Lower Merion is MPC-governed (see above); has residential districts permitting site-built single-family (LDR1, LDR2, LDR3, LDR4, MDR1). §503(1.1) therefore binds: zoning ordinance shall not prohibit manufactured / mobile housing in residential districts where site-built single-family is permitted, nor impose more-restrictive standards.
Effect
Manufactured / mobile housing must be permitted in any district that permits site-built SFR; cannot impose more-restrictive standards than site-built SFR.
PA Surface Mining Conservation and Reclamation Act (SMCRA, 52 P.S. §1396.4e)applies
Qualifying condition
Statewide express preemption per §1396.4e binds all PA municipalities. Montgomery County has no active surface-mining operations of record (suburban / built-out); Lower Merion is overwhelmingly residential / institutional. Practical applicability is latent rather than active.
Effect
Local ordinances regulating surface mining are preempted as to operational / reclamation / environmental standards; municipality may enact MPC-authorized ordinances regulating location consistent with the Act.
Non-applicable laws (1)
PA Act 13 of 2012 §3303 — oil & gas operational preemptiondoes_not_apply
Qualifying condition
Montgomery County is outside the Marcellus Shale and Utica Shale formations; no unconventional gas wells of record in Lower Merion. The §3303 technical/operational preemption is statewide but has no practical bite where no oil/gas operations exist. Recorded for completeness.
Effect
Not applicable in practice — no unconventional gas operations in Lower Merion.
Adopted building codes
Most jurisdictions opt in
Click a code label to open its state-by-state adoption atlas.
Amendment history
| Date | Kind | Citation |
|---|---|---|
| 2026-04-26 | retrieved at | research run |
| 2020-02-26 | adoption | Comprehensive zoning code rewrite adopted by Board of Commissioners (lowermerion.org Building & Planning — 'Zoning Code Adopted 02/26/2020') |
| 2016-03-02 | amendment effective | Floodplain Overlay map updated to reflect FEMA Flood Insurance Study dated March 2, 2016 |
| 2014-01-01 | amendment effective | CAD Bala Village (BV) sub-district adopted under separate ordinance (year confirmed; precise date not retrieved) |
| 2012-01-01 | amendment effective | CAD Regional Center Area (RCA) and Bala Cynwyd Retail (BCR) sub-districts adopted (year confirmed; precise date not retrieved) |
Quirks & notes
- Comprehensive 2020-02-26 zoning code rewrite — replaced legacy Euclidean code with form-based-leaning hybrid. Form Standards tables (4.1 LDR, 4.2 MDR, 4.3 Commercial Center) define dimensional rules; sub-district granularity is high (LDR1-4, MDR1-3, BMV1-4, BMMD1-3, IC1-3, IE1-3, IH1-3, CAD-RCA/BCR/BV). Recent rewrite means legacy aggregator data and pre-2020 underwriting analyses are stale. [severity: high; citation: lowermerion.org Building & Planning — 'New Zoning Code Adopted 02/26/2020']
- Roof-pitch-conditional height bonus in LDR districts: low-sloped roofs limited to 2 stories / 28 ft, but steep-sloped roofs (pitch >5:12 up to 12:12) permitted to 3 stories / 35 ft. Mechanism rewards pitched roofs aesthetically associated with the Main Line traditional architecture vocabulary; pro forma must value pitched-roof framing-cost premium as a height-bonus enabler, not just an aesthetic choice. [severity: high; citation: §155 LDR Form Standards (ecode360.com/35686330)]
- MDR3 transitional step-back rule: when adjacent to LDR / MDR1 / MDR2, MDR3 may rise from baseline 35 ft (2.5 stories) to 50 ft (4 stories) only with a 15-ft front step-back at the 3rd floor or 40 ft height. This is a contextual height taper — not a flat allowance. Massing studies must place transitional units carefully or the bonus disappears. [severity: high; citation: §155 MDR Form Standards]
- 1st-class township governance — 14 commissioners elected by ward (vs Upper Merion's 5 supervisors at-large). PA distinguishes 1st-class townships (≥300 inhabitants/sq mi; ward-based representation) from 2nd-class. Both are MPC-governed but 1st-class commission structure can make zoning amendments more politically granular (ward-level constituency). [severity: medium; citation: Wikipedia Lower Merion Township; PA Code 1st-class township statute]
- Narberth Borough is a separate political entity (~0.5 sq mi) completely surrounded by Lower Merion Township. Narberth has its own zoning code and is not subject to Lower Merion's Chapter 155. Site-level analysis must check borough-vs-township jurisdiction for any parcel near the Narberth boundary. [severity: medium; citation: Wikipedia Lower Merion Township]
- City Avenue District (CAD) has been Lower Merion's primary upzoning instrument: RCA + BCR adopted 2012, BV added 2014. Recent activity concentrates here (The Blayr — 217 apartments / 19,000 sf retail / 2026; broader 2024 Inquirer coverage of City Avenue residential transformation). CAD is the only district where township policy actively pursues mid-rise mixed-use; everywhere else the 2020 rewrite preserves suburban character. [severity: high; citation: lowermerion.org City Avenue Special Services District; Inquirer 2024-05-02 + 2026-04-12 coverage]
- 5 conservation/preservation overlays in Article VII (HR-O Historic, OSP-O Open Space, FP-O Floodplain, SS-O Steep Slope, WL-O Wooded Lot) — among the most comprehensive overlay sets in the corpus. Wooded-Lot overlay in particular is uncommon and is a Main Line preservation signature. Pre-acquisition due diligence must check all 5 overlays per parcel. [severity: high; citation: §155 Article VII Conservation and Preservation Overlays (ecode360.com/35748018)]
- 10 institutional sub-districts (IN, IC1-3, IC civic; IE1-3 education; IH1-3 health) reflect the township's outsized institutional employment base — Bryn Mawr / Haverford / Saint Joseph's / Rosemont / Harcum colleges + Lankenau Medical Center + Bryn Mawr Hospital. Main Line Health is the largest employer. Institutional districts are not interchangeable; tier (1/2/3) matters for FAR and use mix. [severity: medium; citation: §155 Article VI Institutional Districts; lowermerion.org Local Economy and Demographics]
- Single light-industrial district (LI). Lower Merion has effectively no heavy industry — the township summary explicitly states 'one manufacturing district.' This is unusual for a 64K-pop municipality and reflects 80+ years of residential / institutional zoning posture. [severity: low; citation: lowermerion.org Building & Planning Department zoning summary]
Massing explorer
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| District | Category | Height | FAR | Coverage | Setbacks | Parking | Density | Min lot | Overlays |
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Sources & references
Citations
- [1] §155
- [2] §155
- [3] §155
- [4] §155
- [5] §155
- [6] §155
- [7] §155
Research status
Publication gates
| primary url present | passed | |
|---|---|---|
| no aggregator cited | passed | |
| confidence tags full form | passed | |
| overlays have parameters trigger confidence | passed | |
| preempt section city specific | passed |
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