Overview
Code type
euclidean
Naming convention
letter-code
Union is the Franklin County seat (~12,500 population). v1 profile was severely template-bleed corrupted: 55 'districts' all named with markdown header fragments ('**Minimum Lot Area**', '**Lot Width**', '**Max Height**', etc.) extracted incorrectly from a column-heading table in the source markdown — these were not actual zoning districts. All 55 also carried identical fabricated dimensional values (5000/35/0.5/0.5/2/25/25/10). Per FM-6 anti-fabrication, the entire districts array has been REMOVED in v2 rather than retained. Code type is presumed Euclidean (standard for small non-charter MO cities) but specific district inventory requires primary-source retrieval. Code source URL not present in v1 — Union does not appear to host on Municode or eCode360 under a standard identifier; likely needs city planning department direct contact.
Worth knowing
- v1 PROFILE WAS TEMPLATE-BLEED CORRUPT: 55 'districts' all markdown-header fragment names with identical fabricated dimensional values. v2 STRIPS this corruption per FM-6 anti-fabrication discipline. District inventory recovery is the top data gap.
- Franklin County seat status — city/county interaction is unusually direct compared to peer non-county-seat MO cities. County zoning under Chapter 64 controls unincorporated land directly adjacent to municipal limits.
- I-44 corridor position drives commercial-highway frontage development pressure.
+ 1 more in Quirks & notes
State preemptions
MO RSMo Chapter 89 (Zoning and Planning)applies
Qualifying condition
RSMo Chapter 89 §§89.020-89.110 (Standard State Zoning Enabling Act derivative). Non-charter city (likely third-class under RSMo Chapter 77 or fourth-class under Chapter 79 — population ≈ 12,500, above 5,000 charter-eligibility threshold but not chartered as of available record). Franklin County seat.. Zoning authority derives from Chapter 89 (universal enabling for MO municipalities) layered with home-rule authority where applicable. Citation-date 1939 is a conservative codification-start estimate; Chapter 89 has been continuously in force throughout the modern MO zoning regime.
Effect
Zoning ordinance must comply with §89.040 'in accordance with a comprehensive plan' standard and §89.050 procedural floor (15-day published notice, public hearing, two-thirds supermajority on protest petition). Rezonings subject to §89.060 protest petition (30% area / 30% within 185 ft).
MO RSMo §89.020.2 (manufactured-home appearance preemption)applies
Qualifying condition
RSMo §89.020.2 enacted via SB 644 (2006) — citation flagged for re-verification in preemptions.md retrieval-issues. Permissive preemption: applies to all MO municipalities including Non-charter city (likely third-class under RSMo Chapter 77 or fourth-class under Chapter 79 — population ≈ 12,500, above 5,000 charter-eligibility threshold but not chartered as of available record). Franklin County seat.. City may adopt reasonable appearance criteria (foundation, pitch, width) for HUD-Code manufactured homes in single-family districts but is not compelled to permit them universally. Status per_parcel_conditional because effective constraint depends on whether the city permits manufactured homes in any single-family district at all.
Effect
If the city permits manufactured homes in any single-family residential district, it may impose reasonable appearance criteria. The city may also lawfully not permit HUD-Code manufactured homes outside designated MH districts so long as zoning is not internally discriminatory.
MO RSMo §700.027 (modular-unit state code equivalence)applies
Qualifying condition
RSMo §700.027 — Statewide modular-unit state code; equivalence with site-built. Applies to all MO municipalities. Citation-date 1986 is a conservative estimate for chapter codification — re-verify against revisor.mo.gov for exact enacting session law.
Effect
Modular units (built to MO state code) are treated as equivalent to site-built dwellings; cannot be excluded from districts that permit site-built dwellings of the same type.
MO Hancock Amendment — Mo. Const. Art. X §§16–24applies
Qualifying condition
Mo. Const. Art. X §§16–24 (Hancock Amendment; 1980 voter initiative). Statewide constitutional limit. Applies to Non-charter city (likely third-class under RSMo Chapter 77 or fourth-class under Chapter 79 — population ≈ 12,500, above 5,000 charter-eligibility threshold but not chartered as of available record). Franklin County seat. for any new fee or fee increase since 1980-11-04 (per Keller v. Marion County Ambulance District, 820 S.W.2d 301 (Mo. banc 1991) five-factor fee/tax test). Materially constrains impact-fee adoption — most MO cities do not levy transportation/parks impact fees under the Keller framework.
Effect
City may not levy a new tax/license/fee or increase existing such revenue source above 1980-11-04 level without voter approval. Practical effect on zoning: building-permit and plan-review fees OK if cost-of-service; transportation/parks impact fees structurally difficult under Keller test; no general MO impact-fee enabling statute. Capital infrastructure funding typically via TIF/CID/TDD or voter-approved sales-tax mechanisms (§94.577) rather than impact fees.
MO RSMo §89.145 (group homes for persons with disabilities)applies
Qualifying condition
RSMo §89.145 — Statewide. Applies to all MO municipalities including Non-charter city (likely third-class under RSMo Chapter 77 or fourth-class under Chapter 79 — population ≈ 12,500, above 5,000 charter-eligibility threshold but not chartered as of available record). Franklin County seat.. Parallels federal Fair Housing Act but codified at state level. Citation-date 1989 is a conservative estimate — re-verify enacting session law against revisor.mo.gov.
Effect
Municipalities may not prohibit group homes of ≤8 unrelated persons with disabilities in any single-family zone.
MO HB 595 (2025) — source-of-income discrimination preemptionapplies
Qualifying condition
HB 595 (2025, 103rd G.A., 1st Reg. Sess.; Brown / Schroer), signed by Gov. Kehoe, effective 2025-08-28. Statewide — applies to all MO municipalities. Preempts municipal source-of-income discrimination ordinances and local restrictions on landlord background-check / security-deposit / right-of-first-refusal practices.
Effect
City cannot enact or enforce a source-of-income discrimination ordinance restricting landlord refusal based on tenant income source (including Section 8 vouchers). Tenant-screening / landlord-tenant practice rather than land use per se, but operates adjacent to fair-housing zoning policy.
MO RSMo Chapter 64 (county planning, zoning, recreation) — ETJ interactionapplies
Qualifying condition
RSMo Chapter 64 — Franklin County operates county zoning (or charter zoning if home-rule) under Chapter 64 class-specific subchapters. Applies only to UNINCORPORATED portions; does not directly preempt Non-charter city (likely third-class under RSMo Chapter 77 or fourth-class under Chapter 79 — population ≈ 12,500, above 5,000 charter-eligibility threshold but not chartered as of available record). Franklin County seat. zoning within municipal limits. Status per_parcel_conditional because effective constraint depends on whether the parcel sits inside or outside corporate limits.
Effect
County zoning controls land in unincorporated portions of the county and may affect the city's extraterritorial jurisdiction (ETJ) interactions and annexation patterns. Within municipal limits, Chapter 89 (not Chapter 64) governs.
Non-applicable laws (1)
MO statewide STR preemption (none in force)does_not_apply
Qualifying condition
No codified statewide STR-preemption statute. Bills SB 415/HB 615 (2024), SB 742/HB 482 (2025), refiled in 2026 session — none enacted as of 2026-05 review. SB 1066/HB 1768 (2026) passed both chambers, awaiting gubernatorial action — property-tax classification of STRs, not zoning preemption. Sentinel effective_date 1900-01-01 used to flag 'no enacting date'.
Effect
City retains full Chapter 89 / home-rule authority to regulate, cap, or prohibit short-term rentals subject only to federal constitutional and state uniform-ordinance constraints. Watch list: 2026 session HB 5529–5585 zoning-preemption block (posted to House Government Operations May 2026; outcome pending) and SB 1066/HB 1768 STR property-tax classification.
Adopted building codes
Local adoption
Click a code label to open its state-by-state adoption atlas.
Quirks & notes
- v1 PROFILE WAS TEMPLATE-BLEED CORRUPT: 55 'districts' all markdown-header fragment names with identical fabricated dimensional values. v2 STRIPS this corruption per FM-6 anti-fabrication discipline. District inventory recovery is the top data gap.
- Franklin County seat status — city/county interaction is unusually direct compared to peer non-county-seat MO cities. County zoning under Chapter 64 controls unincorporated land directly adjacent to municipal limits.
- I-44 corridor position drives commercial-highway frontage development pressure.
- Zoning code host identification is the top retrieval task — not currently observed on Municode or eCode360 under standard slugs.
Formulas
Definitions
- height
- Grade to highest point of structure.
- 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 dwelling unit unless noted.
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
—
——
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 |
|---|
Research status
Publication gates
| primary url present | passed | source.primary_url = unionmissouri.gov (city portal homepage). v1 had no code_source URL at all. This satisfies Gate 1 ('a URL exists, https, not an aggregator') but is acknowledged as a city-portal URL rather than the zoning code itself; full primary-source upgrade is recorded as the top data gap. secondary_url = franklinmo.net (county portal) for ETJ / county zoning context. |
|---|---|---|
| no aggregator cited | passed | No Zoneomics / Steadily / SitePlanGuide / PropertyShark citations. All references are to the city/county municipal portals and standard MO preemption sources. |
| confidence tags full form | passed | v1 district data was template-bleed corrupted (55 districts, all markdown-header fragment names, 1 unique signature across 55 entries — universal 5000/35/0.5/0.5/2/25/25/10 fabricated values). Per FM-6 ('Fabricate values to fill schema slots') the entire fabricated district array has been REMOVED in v2 and replaced with an empty districts array plus an explicit quality.gaps entry documenting the corruption and the recovery path. This is the correct treatment of fabricated values — not 'downgrade to partial', but 'remove and document gap'. |
| overlays have parameters trigger confidence | passed | v1 overlays array was empty. v2 preserves this honest empty state — no fabricated overlays. Missing-overlay-coverage documented as quality.gap. |
| preempt section city specific | passed | state_preemptions_applicable[] contains 8 Union-specific entries per preemptions.md. MO-RSMo-89.020.2 applies_permissive given non-charter status. MO-RSMo-64 noted: Union is the Franklin County seat, so the city-county interaction is unusually direct. |
Data quality
35%completeness
Documented gaps
- v1 districts were template-bleed corrupted (markdown-header fragment names + identical fabricated dimensional values across all entries). STRIPPED in v2 per FM-6 anti-fabrication. Full district-inventory recovery requires primary-source identification and retrieval.
- Quirks not populated — requires markdown source review
Other cities in this state
Nearest-alphabetical profiles. Click through to compare zoning patterns side-by-side.