Overview
Code type
euclidean
Naming convention
mixed
Standard Illinois letter-number convention. R-prefix residential (R-1A largest-lot SF, R-1B mid SF, R-2 standard SF, R-3A/R-3 townhouse, R-4 multi-family, R-5 high-density MF), B-prefix business (B-1 local, B-2 community, B-3 general, B-4 highway, B-5 — pending specific definition), OCI (Office-Commercial-Institutional), ORI (Office-Research-Industrial — east-west tollway research corridor), I (Industrial). Special-purpose districts: E2/E3 (Estate residential, low-density large-lot), AG (Agricultural — remnant rural fringe), HS (Health Services — Edward Hospital area), BP (Business Park), TU (likely Transition/Urban or Transit), 'College/University' (North Central College + Naperville campus zones), RD (Research and Development). Downtown Naperville (around Washington/Jackson/Main) operates under additional small-area-plan overlays including the North Downtown Plan area. The 5th Avenue Station Redevelopment Area (around Metra BNSF station, planned high-density mixed-use) is a major active small-area plan as of 2025-2026. | naming_convention_raw=letter-number ; sub_flags_raw=[home-rule-jurisdiction, high-affluence-suburb, research-and-development-corridor-east-west-tollway, downtown-special-rules-rit-rib, 5th-avenue-station-redevelopment-area, dupage-county-corporate-limits-and-will-county-spillover, naperville-park-district-major-open-space, ofs-overlay-floodplain-stormwater-prairie-path-corridor] ; narrative_ref=narratives/naperville-il/v2-regen-20260518.json
Worth knowing
- Naperville straddles two counties — primarily DUPAGE, with a small spillover into WILL County. County-line affects Plat Act recording (765 ILCS 205) but NOT zoning authority — Naperville's home-rule zoning applies throughout corporate boundaries. — [US Census Bureau place-county relationship file; Naperville corporate boundary GIS]
- Naperville is a DuPage home-rule city (149,540 ≫ 25k threshold). State enabling-act procedural requirements do NOT bind. v1 cited 'state-preemptions/illinois.md' — relative path is correct but v1 did not actually evaluate per-statute applicability. v2 evaluates 12 IL preemptions city-specifically. — [Ill. Const. 1970 Art. VII §6(a); 2020 Census]
- Naperville's east-west tollway research corridor (Office-Research-Industrial / RD districts) is the operational legacy of Lucent Technologies / Bell Labs (Naperville-Lisle Corporate Research Center) — one of the largest concentrations of corporate R&D outside the Bay Area through the 1990s. The ORI / RD framework reflects this lineage; current tenants include BMO Innovation Hub, Calamos Investments, and other financial / tech firms. — [Naperville Title 6 ORI/RD districts; Naperville-Lisle Corporate Research Center history]
+ 6 more in Quirks & notes
Districts
res_sf 5com 5off 4res_mf 3spec 3res_th 1ag 1ind 1mu 1
| Code | Name | Category | Min lot | Height | Coverage | FAR | Du/ac | Parking | Setbacks F/S/R |
|---|---|---|---|---|---|---|---|---|---|
| R-1A | Estate Residential — Large Lot (R-1A) | res_sf | — | — | — | — | — | — | — / — / — |
| R-1B | Single-Family Residential — Standard (R-1B) | res_sf | — | — | — | — | — | — | — / — / — |
| R-2 | Single-Family Residential (R-2) | res_sf | — | — | — | — | — | — | — / — / — |
| R-3A | Townhouse / Attached Residential (R-3A) | res_th | — | — | — | — | — | — | — / — / — |
| R-3 | Multi-Family Residential (R-3) | res_mf | — | — | — | — | — | — | — / — / — |
| R-4 | Multi-Family Residential (R-4) | res_mf | — | — | — | — | — | — | — / — / — |
| R-5 | High-Density Multi-Family (R-5) | res_mf | — | — | — | — | — | — | — / — / — |
| E2 | Estate Residential (E2) | res_sf | — | — | — | — | — | — | — / — / — |
| E3 | Estate Residential (E3) | res_sf | — | — | — | — | — | — | — / — / — |
| AG | Agricultural (AG) | ag | — | — | — | — | — | — | — / — / — |
| B-1 | Neighborhood Business (B-1) | com | — | — | — | — | — | — | — / — / — |
| B-2 | Community Business (B-2) | com | — | — | — | — | — | — | — / — / — |
| B-3 | General Business (B-3) | com | — | — | — | — | — | — | — / — / — |
| B-4 | Highway/Regional Business (B-4) | com | — | — | — | — | — | — | — / — / — |
| B-5 | Business — Tier 5 (B-5) | com | — | — | — | — | — | — | — / — / — |
| OCI | Office-Commercial-Institutional (OCI) | off | — | — | — | — | — | — | — / — / — |
| ORI | Office-Research-Industrial (ORI) | off | — | — | — | — | — | — | — / — / — |
| I | Industrial (I) | ind | — | — | — | — | — | — | — / — / — |
| RD | Research and Development (RD) | off | — | — | — | — | — | — | — / — / — |
| HS | Health Services (HS) | spec | — | — | — | — | — | — | — / — / — |
| BP | Business Park (BP) | off | — | — | — | — | — | — | — / — / — |
| TU | Transit/Urban (TU) | mu | — | — | — | — | — | — | — / — / — |
| C/U | College / University District | spec | — | — | — | — | — | — | — / — / — |
| PUD | Planned Unit Development | spec | — | — | — | — | — | — | — / — / — |
Confidence: confirmed partial under review not found
Overlays
DT
Downtown Naperville Small-Area Plan
DTDowntown Naperville (around Washington/Jackson/Main streets, Naperville Riverwalk, downtown commercial core). Small-area plan adopted via Naperville Plan Commission; supplements Title 6 base-district rules.
| review_authority | Naperville Planning and Zoning Commission + City Council |
|---|---|
| intent | Preserve pedestrian-oriented downtown character; manage building height + facade transparency adjacent to Riverwalk |
| specific_article | pending Municode SPA bypass |
NDT
North Downtown Small-Area Plan
DTNorth Downtown Naperville (Jackson Avenue north to north corporate limits) — small-area plan governing the redevelopment of formerly-light-industrial parcels for mixed-use.
| review_authority | Naperville Planning and Zoning Commission + City Council |
|---|---|
| intent | Transition former industrial parcels to mixed-use density |
| specific_article | pending Municode SPA bypass |
5AVE
5th Avenue Station Redevelopment Area
TOD5th Avenue Station Redevelopment Area surrounding the BNSF Metra Naperville Downtown station — planned high-density mixed-use redevelopment, active as of 2025-2026. Functions as a Naperville-specific TOD overlay (not the same as Chicago's ETOD).
| review_authority | Naperville Planning and Zoning Commission + City Council; concept plan adopted 2017, refined 2023 |
|---|---|
| intent | High-density mixed-use within ¼-½ mi of BNSF Metra Naperville station |
| specific_article | pending Municode SPA bypass |
WS-TIF
Water Street District Tax Increment Financing
SPDWater Street District — riverwalk-adjacent downtown TIF (mixed-use redevelopment along the DuPage River south bank). State framework at 65 ILCS 5/11-74.4 governs.
| max_term_years | 23 |
|---|---|
| designation_authority | Naperville City Council ordinance after JRB |
| findings_required | blight, conservation, or industrial-park |
| use_of_increment | redevelopment-project costs per 65 ILCS 5/11-74.4-3 |
HD
Historic District / Landmark
HPDesignated historic districts and individual landmarks (Naperville Historic District around Naper Settlement / Central Park / Park Addition). Title 6 historic-preservation article.
| design_review_required | True |
|---|---|
| review_authority | Naperville Historic Preservation Commission |
| demolition_review_required | True |
| specific_article | pending Municode SPA bypass |
FP
Floodplain Overlay
FPFEMA Special Flood Hazard Areas along the DuPage River, Spring Brook, and tributaries per DuPage County FIRM panels.
| fema_floor_elevation_required | True |
|---|---|
| fema_administered | Naperville participates in NFIP; FEMA FIRM panels govern delineation |
| primary_basins | DuPage River + Spring Brook |
TDI
Tear-Down / Infill Restrictions
CONEstablished residential neighborhoods where infill teardowns trigger additional design / massing / setback / floor-area restrictions to manage neighborhood-character impacts.
| intent | Manage mass / height / setback impacts of teardown-rebuilds on established residential blocks |
|---|---|
| specific_article | pending Municode SPA bypass; v1 referenced this as 'Tear-Down/Infill Special Restrictions' |
State preemptions
IL-home-ruleapplies
Qualifying condition
Naperville 2020 Census population 149,540 ≫ 25,000 automatic-home-rule threshold per Art. VII §6(a). | statute=Ill. Const. 1970, Art. VII §6(a)
Effect
Naperville zones under Art. VII §6 home-rule authority via Title 6. State enabling act (65 ILCS 5/11-13-1 to 5/11-13-14) procedural requirements do not bind unless GA expressly applied.
IL-65ILCS5-11-13-25-manufactured-housingapplies
Qualifying condition
Statewide anti-exclusion rule binds Naperville. Must permit HUD-Code manufactured homes in residential districts on the same footing as site-built homes, subject to aesthetic/siting standards. | statute=65 ILCS 5/11-13-25 (manufactured-housing anti-exclusion)
Effect
Floor on local exclusion; Naperville retains aesthetic and siting controls.
IL-310ILCS67-AHPAAapplies
Qualifying condition
Naperville is widely understood to be a high-affluence suburb with affordable-housing stock below the 10% AHPAA threshold. Whether Naperville is on the 2023 IHDA NELG list of 44 municipalities is the gating fact — independent verification of the 2023 NELG list against Naperville pending direct IHDA PDF retrieval; project memory indicates several west-suburban DuPage/Will municipalities are on NELG. Marking applies_NELG provisionally pending NELG-list cross-check. If confirmed, Naperville must adopt an Affordable Housing Plan + SHAB-override available against denials of qualifying affordable developments. | statute=310 ILCS 67 (Affordable Housing Planning and Appeal Act)
Effect
If NELG-listed: SHAB-override mechanism available; Naperville must adopt affordable-housing plan with measurable production targets. Binds home-rule via GA 3/5 supermajority at original enactment.
IL-PA102-1123-wind-solarapplies
Qualifying condition
Naperville does not currently host commercial wind or utility-scale solar facilities — densely-developed suburb. If a facility is proposed, statute caps local standards at state-default. | statute=55 ILCS 5/5-12020 + 5-12020.1; PA 102-1123
Effect
Setback, height, decommissioning, noise standards for commercial wind/solar may not exceed state default.
IL-65ILCS5-11-74-4-TIFapplies
Qualifying condition
Naperville has had multiple TIF districts including the Water Street TIF (downtown riverwalk-adjacent) and 5th Avenue Station Redevelopment area. Each follows statewide framework: blight/conservation/industrial-park findings, redevelopment plan, JRB, public hearing, ordinance, 23-year max term. | statute=65 ILCS 5/11-74.4 (Tax Increment Allocation Redevelopment Act)
Effect
TIF designation and term capped by statute; drives redevelopment-eligible costs and indirectly land-use in TIF boundaries.
IL-71-Ill-Adm-Code-400-accessibilityapplies
Qualifying condition
Statewide accessibility floor binds Naperville construction. | statute=71 Ill. Adm. Code 400 (Illinois Accessibility Code); 410 ILCS 25
Effect
Floor — Naperville may layer stricter standards.
IL-415ILCS5-39-2-pollution-control-sitingapplies
Qualifying condition
Naperville's I/ORI districts could host pollution-control facilities but the developed-suburb profile makes new siting unlikely. Statute and IPCB appeal path remain available if proposed. | statute=415 ILCS 5/39.2 (Environmental Protection Act — local pollution-control siting)
Effect
Local siting decisions on landfill/transfer-station/hazwaste appealable to IPCB.
IL-770ILCS60-mechanics-lienapplies
Qualifying condition
State-exclusive lien-priority regime binds Naperville notwithstanding home-rule. | statute=770 ILCS 60 (Mechanics Lien Act)
Effect
Naperville cannot alter mechanics-lien priority by local ordinance.
IL-765ILCS205-plat-actapplies
Qualifying condition
Subdivision recording is state-controlled via DuPage County Recorder (primary; Will County Recorder for the small Will-County portion of Naperville). | statute=765 ILCS 205 (Plat Act)
Effect
Plat recording procedure binds Naperville platting.
IL-35ILCS145-hotel-tax-STRapplies
Qualifying condition
Statewide hotel tax reaches STRs as 'hotel operators'; platforms remit under marketplace-facilitator rules. Naperville local STR zoning is NOT preempted. | statute=35 ILCS 145 (Hotel Operators' Occupation Tax Act)
Effect
Tax side only; STR zoning remains home-rule.
Non-applicable laws (2)
IL-BUILD-Plan-HB5626-pendingunder_review
Qualifying condition
As of 2026-05-18, BUILD Plan is in committee — not enacted. If signed (Jan 1 2027 effective date), Naperville would be bound (home-rule >25k) by ADU-by-right + parking-minimum elimination ½ mi from transit. Naperville has the BNSF Metra Downtown station + Route 59 Metra station (one of Metra's highest-ridership commuter stations) — significant residential blocks within ½-mi buffer of both. | statute=HB 5626 + companion SBs 4060-4064/4071 (104th GA); Pritzker BUILD Plan
Effect
Not currently in force. Track for next freshness pass.
IL-Connected-Communities-HB4083-SB2352-pendingunder_review
Qualifying condition
Pending Illinois Connected Communities Act. Naperville's BNSF Metra Downtown station + Route 59 station would trigger ½-mi ADU-by-right + parking-minimum elimination. | statute=HB 4083 / SB 2352 (104th GA)
Effect
Not currently in force.
Adopted building codes
No statewide building code
Click a code label to open its state-by-state adoption atlas.
Quirks & notes
- Naperville straddles two counties — primarily DUPAGE, with a small spillover into WILL County. County-line affects Plat Act recording (765 ILCS 205) but NOT zoning authority — Naperville's home-rule zoning applies throughout corporate boundaries. — [US Census Bureau place-county relationship file; Naperville corporate boundary GIS]
- Naperville is a DuPage home-rule city (149,540 ≫ 25k threshold). State enabling-act procedural requirements do NOT bind. v1 cited 'state-preemptions/illinois.md' — relative path is correct but v1 did not actually evaluate per-statute applicability. v2 evaluates 12 IL preemptions city-specifically. — [Ill. Const. 1970 Art. VII §6(a); 2020 Census]
- Naperville's east-west tollway research corridor (Office-Research-Industrial / RD districts) is the operational legacy of Lucent Technologies / Bell Labs (Naperville-Lisle Corporate Research Center) — one of the largest concentrations of corporate R&D outside the Bay Area through the 1990s. The ORI / RD framework reflects this lineage; current tenants include BMO Innovation Hub, Calamos Investments, and other financial / tech firms. — [Naperville Title 6 ORI/RD districts; Naperville-Lisle Corporate Research Center history]
- The 5th Avenue Station Redevelopment Area is the major active small-area plan as of 2025-2026 — high-density mixed-use redevelopment around the BNSF Metra Naperville Downtown station (one of Metra's highest-ridership commuter stations). Functions as a Naperville-specific TOD overlay but is NOT 'ETOD' (which is a Chicago-only 2022 Connected Communities ordinance framework). — [Naperville 5th Avenue Station Redevelopment Plan (2017 concept; 2023 refinement)]
- Naperville's Water Street District TIF (downtown riverwalk-adjacent) is a high-profile TIF anchoring mixed-use redevelopment along the DuPage River's south bank. State framework 65 ILCS 5/11-74.4. v1 carried 'Water Street Tax Increment Financing' as overlay but with fabricated 'height multiplier: -0.05' parameter; v2 anchors it to the state TIF framework instead. — [Naperville Water Street District TIF designation; 65 ILCS 5/11-74.4]
- AHPAA NELG status — Naperville is widely understood to be a high-affluence suburb with affordable-housing stock below the 10% AHPAA threshold. v2 marks IL-310ILCS67-AHPAA as applies_NELG PROVISIONALLY pending direct 2023 NELG-list PDF verification. If confirmed NELG-listed, Naperville must adopt an Affordable Housing Plan with measurable production targets + SHAB-override available against denials of qualifying affordable developments. This is one of the higher-consequence per-record overlay flags in IL. — [310 ILCS 67/15, 67/20, 67/30, 67/60; 2023 NELG list (IHDA biennial) pending direct verification]
- v1 profile carried fabricated numeric overlay parameters across 5 overlays (Historic / Water Street TIF / North Downtown / 5th Avenue / Tear-Down Infill — 'height multiplier: -0.05', 'FAR multiplier: 0.05', 'coverage adjustment (%)': -10, 'density multiplier: -0.2', 'lot size multiplier: 0.15'). These template-bleed values do not correspond to any provision of Naperville Title 6 — actual overlays operate procedurally (small-area plan Plan Commission review, JRB for TIF, design-review for Historic, infill-restrictions floor on teardowns) rather than via numeric multipliers on base-district bulk. v1 'overlay codes' were also nonsense (e.g. 'code: T6' or 'code: RIT6' — likely an artifact of the Title-6 prefix bleeding into the code field). — [v1 overlay schema — fabricated; corrected in v2]
- Tear-Down / Infill Restrictions are a Naperville-distinctive overlay — established residential blocks (often 1960s-1980s subdivisions in older neighborhoods) trigger additional design / massing / setback / floor-area restrictions to manage neighborhood-character impacts of teardown-rebuilds. This is a common quirk in high-affluence inner-ring suburbs (similar frameworks exist in Wilmette, Hinsdale, Glenview). Specific Naperville article anchor pending Municode SPA bypass. — [Naperville Title 6 — tear-down/infill provisions]
- Pending IL Connected Communities Act (HB 4083 / SB 2352, 104th GA) and Pritzker BUILD Plan (HB 5626) would, if enacted, mandate ADU-by-right + parking-minimum elimination within ½ mi of transit. Naperville has TWO Metra stations on the BNSF line (Naperville Downtown + Route 59) — Route 59 is one of Metra's highest-ridership commuter stations system-wide. Significant residential blocks within ½-mi buffer of both. Track for next freshness pass — this is materially higher-impact for Naperville than for inner-ring suburbs because of Route 59's commuter volume. — [HB 5626 + HB 4083 / SB 2352 (104th GA); Metra BNSF schedule + Route 59 station ridership]
Formulas
Definitions
- height
- Grade to highest point of structure (standard Illinois municipal definition; pending §-pinpoint extraction from Title 6 Chapter 3 Definitions).
- lot_coverage
- Building footprint / lot area.
- far
- Gross floor area / lot area.
- du_ac
- Dwelling units per gross acre.
- setback_front
- Front property line to nearest building face.
- setback_side
- Side property line to nearest building face.
- setback_rear
- Rear property line to nearest building face.
- parking
- Spaces per use type; pending Title 6 Chapter 9 Parking extraction.
Capacity calculations
- max_footprint_sf
lot_area_sf * lot_coverage- max_gfa_sf
lot_area_sf * far- buildable_width_ft
lot_width_ft - setback_side_ft * 2- buildable_depth_ft
lot_depth_ft - setback_front_ft - setback_rear_ft- max_stories_approx
max_height_ft / 10
Massing explorer
Interactive 3D comparison across every district. Drag to orbit, scroll to zoom, use the slider to walk districts, and toggle applicable overlays in the right-side panel.
Sort by
Max height
— ft
——
Floor area ratio
—
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Lot coverage
—%
——
Setbacks (F / S / R)
— ft
——
Parking
— /unit
——
Max density
— du/ac
——
Min lot size
— sf
——
Copy zoning profile
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| District | Category | Height | FAR | Coverage | Setbacks | Parking | Density | Min lot | Overlays |
|---|
Sources & references
Primary source
Naperville's zoning code is Title 6 of the Municipal Code, hosted on Municode (library.municode.com/il/naperville). Municode is a known SPA blocker — direct WebFetch returns the AngularJS shell only. The Planning & Zoning Commission page on naperville.il.us returned HTTP 404 to WebFetch this run. Title 6 chapter structure was confirmed via Municode TOC URL fragments visible to search engines: Chapter 1 (Zoning Title; Purposes), Chapter 2 (General Zoning Provisions), Chapter 3 (Definitions), Chapter 4 (Administration; Procedures), Chapter 5 (Zoning Districts; Map), Chapter 6+ (specific district regulations). District inventory was previously partially extracted in v1 as R1A/R1B/R2/R3A/R3/R4/R5, B1/B2/B3/B4/B5, OCI, ORI, I, plus E2/E3/AG/HS/BP/TU/'College/University'/RD. Per v1, all numeric values were template-bleed (universal 5,000 sf min, 0.5 FAR, 35 ft height) — REMOVED in v2 rather than retained. Naperville is a DuPage County home-rule city (population 149,540 ≥ 25,000 Art. VII §6 automatic-home-rule threshold). Small portion extends into Will County.
Research status
Publication gates
| primary url present | passed | source.primary_url = library.municode.com/il/naperville/codes/code_of_ordinances?nodeId=TIT6ZORE (Municode canonical host of Title 6) + secondary_url = naperville.il.us Planning and Zoning Commission page + tertiary_url = Chapter 5 (Zoning Districts; Map) deep link. v1 had no publication block. |
|---|---|---|
| no aggregator cited | passed | No Zoneomics / Steadily / SitePlanGuide / PropertyShark citations. All citations are to Naperville Title 6, Illinois Compiled Statutes (65 ILCS 5/11-13, 65 ILCS 5/11-74.4, 65 ILCS 5/11-13-25, 310 ILCS 67, 770 ILCS 60, 765 ILCS 205, 35 ILCS 145), Illinois Constitution Art. VII §6, IL state-overlays.json, and Naperville small-area plans (Downtown, North Downtown, 5th Avenue Station, Water Street District TIF). |
| confidence tags full form | passed | All confirmed claims carry citation strings to specific statute / ordinance / chapter references. Partial claims (district dimensional values, specific overlay article numbers) carry explicit status:'partial' with reason field citing Municode SPA blocker. No bare [confirmed] tags. The numeric template-bleed values from v1 have been REMOVED (not retained with partial confidence) because they were fabricated, not partial. |
| overlays have parameters trigger confidence | passed | 7/7 overlays (Downtown Naperville Small-Area Plan, North Downtown Small-Area Plan, 5th Avenue Station Redevelopment Area, Water Street District TIF, Historic District / Landmark, Floodplain, Tear-Down/Infill Restrictions) each have non-empty params + trigger + status + citation. 1 confirmed (Water Street District TIF, anchored to state framework), 6 partial pending Municode SPA bypass for specific Title 6 article anchors. |
| preempt section city specific | passed | state_preemptions_applicable[] contains 12 Naperville-specific entries — each with city-specific qualifying_condition_checked (Naperville pop 149,540 ≫ 25k home-rule threshold; AHPAA applies_NELG provisionally pending 2023 list verification; DuPage County (+ Will County spillover) Plat Act recording; two BNSF Metra stations including high-ridership Route 59 trigger BUILD Plan / Connected Communities ADU+parking preemption if enacted; etc.). v1 cited 'state-preemptions/illinois.md' but did not actually evaluate per-statute. v2 evaluates per-statute. |
Data quality
40%completeness
Documented gaps
- Naperville Title 6 full district dimensional standards — requires Municode SPA bypass (headless browser, CivicPlus PDF mirror, or direct PDF export request to City of Naperville Planning)
- Specific Title 6 article numbers for Downtown / North Downtown / 5th Avenue Station / Historic / Floodplain / Tear-Down-Infill overlays
- Specific Title 6 article number for PUD
- 2023 IHDA NELG list — direct PDF retrieval to verify whether Naperville is among the 44 NELG municipalities (provisional applies_NELG marking depends on this)
- Naperville STR ordinance section
- Naperville ADU framework
- Naperville TIF districts beyond Water Street
- Pritzker BUILD Plan (HB 5626) enactment status — if signed, two BNSF Metra stations (Downtown + Route 59) trigger ½-mi ADU+parking-min preemption with material development impact given Route 59's high ridership
- Connected Communities Act (HB 4083 / SB 2352) enactment status — same as above
- B-5 district specific definition (v1 listed but did not define)
- TU district specific definition (v1 listed but did not define)
- Naperville historic districts inventory (Naper Settlement area + others)
Known issues
freshness:volatiledata:dimensional-standards-not-extractedretrieval:municode-spa-blockedblocker:municode
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