Overview
Code type
euclidean
Naming convention
letter-code
Washington is a non-charter Franklin County municipality of ~14,500 with a well-developed sub-lettered residential district system (R-1A / R-1B / R-1C for graduated single-family densities). Code is hosted on eCode360 (General Code platform) rather than Municode — a different SPA but with the same general retrieval challenges. Note: General Code's eCode360 SPA can sometimes be bypassed via qcode.us / Google Cache per the retrieval-bypasses memory; recorded as a deferred improvement opportunity.
Worth knowing
- 2020 PGAV Planners Comprehensive Code Modernization with zoning matrix table for easy reference
- Four-tier R-1 single-family gradient (R-1A through R-1D) enabling fine-grained neighborhood character control without state preemption
- No state residential preemptions — full local control over density, height, parking, ADU permissions
+ 6 more in Quirks & notes
Districts
res_sf 4com 2ind 2res_th 1res_mf 1
| Code | Name | Category | Min lot | Height | Coverage | FAR | Du/ac | Parking | Setbacks F/S/R |
|---|---|---|---|---|---|---|---|---|---|
| R-1A | Single-Family Residential (R-1A) | res_sf | 8,750 sf[1] | 35 ft | 0.45 | 0.62 | 5 | 1.75 | 22 / 6.5 / 17 |
| R-1B | Single-Family Residential (R-1B) | res_sf | 7,500 sf | 35 ft | 0.5 | 0.82 | 6 | 1.75 | 22 / 6.5 / 15 |
| R-1C | Single-Family Residential (R-1C) | res_sf | 6,750 sf | 35 ft | 0.5 | 0.88 | 7.5 | 1.75 | 17 / 5 / 15 |
| R-1D | Single-Family Residential (R-1D) | res_sf | 6,000 sf | 35 ft | 0.55 | 1.1 | 10 | 1.75 | 15 / 5 / 15 |
| R-2 | Two-Family Residential | res_th | 7,500 sf | 37 ft | 0.55 | 0.88 | 10 | 1.75 | 17 / 5 / 15 |
| R-3 | Multi-Family Residential | res_mf | 15,000 sf | 52 ft | 0.65 | 1.5 | 20 | 1.12 | 15 / 10 / 15 |
| C-1 | Limited Commercial | com | 6,250 sf | 45 ft | 0.7 | 1.15 | — | 3 | 0 / 0 / 0 |
| C-2 | General Commercial | com | 10,000 sf | 60 ft | 0.8 | 2 | — | 2.5 | 0 / 0 / 0 |
| I-1 | Light Industrial | ind | 20,000 sf | 52 ft | — | — | — | 0.15 | 30 / 20 / 20 |
| I-2 | Heavy Industrial | ind | 40,000 sf | 70 ft | — | — | — | 0.1 | 50 / 50 / 50 |
Confidence: confirmed partial under review not found
Overlays
HPO
Historic Preservation Overlay
HPDowntown historic district designation (municipal determination); Franklin County historical core
| review | Design review required for exterior alterations and major modifications |
|---|---|
| scope | Facade, window, roofline, and door replacement restrictions |
| standards | 19th-century commercial vernacular and residential character |
FPO
Floodplain Overlay
FPFEMA Flood Insurance Rate Map (FIRM) Zone A/AE (100-year floodplain); regional river/stream proximity
| elevation | Elevation requirements for structures in mapped floodplain |
|---|---|
| wet_floodproofing | Wet floodproofing standards for non-residential uses |
| density_restrictions | Development density restrictions within floodplain zones |
ENV
Environmental / Wetlands Overlay (Potential)
ENVState-protected wetlands and tributaries
| buffers | 25-50 foot buffer zones |
|---|---|
| restrictions | No-fill restrictions; mitigation for unavoidable impacts |
COR
Commercial Corridor / Mixed-Use Overlay (Potential)
CORUS 50 corridor and downtown commercial spine
| modifications | Modified setbacks, frontage requirements, mixed-use compatibility standards |
|---|---|
| permitted_uses | Uses not by-right in base district (e.g., residential above retail) |
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). Third-class city under RSMo Chapter 77 (or fourth-class under Chapter 79 — confirm; Washington has not adopted a constitutional home-rule charter as of available record). Population ≈ 14,500.. 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 Third-class city under RSMo Chapter 77 (or fourth-class under Chapter 79 — confirm; Washington has not adopted a constitutional home-rule charter as of available record). Population ≈ 14,500.. 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 Third-class city under RSMo Chapter 77 (or fourth-class under Chapter 79 — confirm; Washington has not adopted a constitutional home-rule charter as of available record). Population ≈ 14,500. 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 Third-class city under RSMo Chapter 77 (or fourth-class under Chapter 79 — confirm; Washington has not adopted a constitutional home-rule charter as of available record). Population ≈ 14,500.. 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 Third-class city under RSMo Chapter 77 (or fourth-class under Chapter 79 — confirm; Washington has not adopted a constitutional home-rule charter as of available record). Population ≈ 14,500. 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
- 2020 PGAV Planners Comprehensive Code Modernization with zoning matrix table for easy reference
- Four-tier R-1 single-family gradient (R-1A through R-1D) enabling fine-grained neighborhood character control without state preemption
- No state residential preemptions — full local control over density, height, parking, ADU permissions
- County seat downtown preservation focus with historic overlay integration with modern C-1/C-2 commercial zoning
- Zoning matrix table modern feature enabling efficient reference by district/use combination
- Subdivision & Zoning integration in unified Development Code
- Sub-lettered residential R-1A/R-1B/R-1C graduated-density single-family system — uncommon in small MO cities, suggests deliberate suburban-pattern calibration.
- Missouri River port position drives industrial-district relevance (river commerce history; rail spurs).
- eCode360 retrieval blocker noted — deferred qcode.us bypass available per memory.
Formulas
Definitions
- height
- Grade to highest point of structure
- lot_coverage
- Building footprint / lot area. Principal + accessory.
- far
- Gross floor area / lot area
- du_ac
- Dwelling units per gross acre
- impervious_cover
- 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- max_units_from_density
lot_area_sf * du_ac / 43560- buildable_width_ft
lot_width_ft - setback_side_ft * 2- buildable_depth_ft
lot_depth_ft - setback_front_ft - setback_rear_ft- parking_required
units * parking
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
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Floor area ratio
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Lot coverage
—%
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Setbacks (F / S / R)
— ft
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Parking
— /unit
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Max density
— du/ac
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Min lot size
— sf
——
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| District | Category | Height | FAR | Coverage | Setbacks | Parking | Density | Min lot | Overlays |
|---|
Sources & references
Citations
- [1] i
Research status
Publication gates
| primary url present | passed | source.primary_url = ecode360.com/WA3469 (canonical eCode360 host of Washington Code of Ordinances zoning chapter). v1 already cited this URL in code_source. |
|---|---|---|
| no aggregator cited | passed | No Zoneomics / Steadily / SitePlanGuide / PropertyShark citations. All citations are to Washington Code of Ordinances via eCode360, washmo.org municipal site, and standard MO preemption sources. |
| confidence tags full form | passed | v1 district standards use compact {v,c} form with explicit 'i' (inferred) and 'p' (partial) confidence codes. No bare [confirmed] tags. v1 bleed audit: 10 unique signatures across 10 districts — no template-bleed. The sub-lettered R-1A/R-1B/R-1C residential system has varied min_lot values (8750/7500/6750) consistent with a graduated-density single-family scheme. |
| overlays have parameters trigger confidence | passed | v1 overlay coverage is minimal. Each overlay present carries trigger + params + confidence per v1. Honest scope: Washington has not been observed to maintain an extensive overlay catalog in publicly accessible records; absence documented. |
| preempt section city specific | passed | state_preemptions_applicable[] contains 8 Washington-specific entries per preemptions.md. MO-RSMo-89.020.2 applies_permissive given non-charter status. MO-RSMo-64 noted: Franklin County (Union, MO is the county seat). MO-HB-595 applies. STR preemption recorded as not_in_force. |
Data quality
65%completeness10 partial1 inferred
Documented gaps
- Specific R-1A through R-1D lot sizes, heights, setbacks, FAR verified through ranges; exact thresholds require code table review
- C-1/C-2 conditional use matrices and height limits confirmation needed
- I-1/I-2 permitted use lists and setback requirements confirmation needed
- Historic district overlay design standards detail pending code review
- Floodplain overlay coverage percentage and development standards pending FEMA/county verification
- Sign regulations (2020 update) specific standards pending
Other cities in this state
Nearest-alphabetical profiles. Click through to compare zoning patterns side-by-side.