Bolthole Index

Clay County, Missouri

Building permits, zoning and septic rules in Smithville, Missouri

Smithville, Missouri requires a city building permit before construction work, including demolition; the Development Department handles building permits and inspections.1 Smithville sets zoning inside city limits, while private sewage disposal requires approval from the health department for the parcel’s county.23 For Smithville parcels in Clay County, start septic questions with the Clay County Public Health Center’s Environmental Health program.45

At a glance

Building permits
City building permit required before work; Development Department handles inspections1
Zoning
City zoning applies; lot and setback rules depend on district2
Private sewage
County health approval, plus submission of the approved permit to the City before construction3
Sewer availability
Public sewer is available when the main is within 100 feet of a property line6
Minimum home size
A-1 and R-1A single-family dwellings: 1,100 square feet of habitable floor area78
Accessory dwellings
Restricted to listed districts; owner occupancy and a certificate of occupancy required9

Who to call

Building permits

Smithville Development Department — Building Inspections

City building permit applications, code questions and building inspections

(816) 866-2056

107 West Main Street Smithville, MO

Zoning

Smithville Planning & Zoning Department

City land-use regulation and planning application intake

(816) 532-3897

107 W. Main, Smithville, MO 64089

Septic permits

Clay County Public Health Center — Environmental Health

Onsite sewage construction and repair permits, site approvals, plan review and construction inspections for Clay County parcels

816-595-4350

800 Haines Drive Liberty, MO 64068

Contact details are copied from each office’s official page and were checked against it on October 12, 2026.

Off-grid gear

Going off-grid in Smithville means bringing your own water and power. The kit we’d start with:

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Do you need a building permit in Smithville, MO?

Smithville’s Building Inspections page requires a building permit before work begins, including demolition.1 Smithville requires a completed New Construction Building Permit Application for new residential construction, home additions and basement finishing, as well as the commercial projects listed on the city page.1 The city has adopted the 2018 International Building Code with city amendments, alongside separate residential and trade-code adoptions.10

Before budgeting an owner-built house or agricultural outbuilding, ask the Smithville Building Inspections office to identify the applicable building permit, exemptions and current fees; we could not confirm a city owner-builder exemption or a complete agricultural building-permit exemption.

Who handles Smithville building permits and zoning applications?

Smithville’s Development Department handles building permits and inspections related to the city’s building codes.1 Call the city’s building-code contact at (816) 866-2056 for building permit and inspection questions.1 Smithville’s Planning & Zoning Department handles land-use regulation under the city code.11

Submit rezoning, subdivision plat, special use, variance and site-plan review applications to the Development Department at 107 W. Main, Smithville, MO 64089.11 Smithville recommends meeting with the Planning Director before filing to determine which applications are needed.11 County health approval remains a separate requirement for a private sewage disposal system inside Smithville.3

Does Smithville have zoning, lot-size rules and setbacks?

Smithville has city zoning with district-specific use and dimensional requirements.2 In Smithville’s R-1A Single-Family Suburban Dwelling District, the minimum lot area is 10,000 square feet and maximum lot coverage is 30%.1213 R-1A side yards must be at least 7.5 feet and rear yards at least 20 feet.14

In Smithville’s A-1 Agricultural District, the minimum side yard is 10 feet and the minimum rear yard is 20 feet.15 A-1 front setbacks are 55 feet from the street centerline on local roads, 60 feet on collectors and 70 feet on arterials, with a separate right-of-way rule for wider arterials and additional corner-lot conditions.15 Ask Smithville Planning & Zoning to identify the parcel’s district and road classification before placing a house on a site plan.

How do septic permits work inside Smithville?

Smithville defines public sewer as available when the sewer main is within 100 feet of a property line; the connection rule applies to new buildings that city plumbing or building codes require to connect.6 The City may determine that connection is impractical because of distance, obstacles, cost or other considerations.6

A Smithville private sewage disposal system requires county health approval and generally a lot of at least 3 acres; a smaller lot may qualify only under the exception for lots platted before October 20, 1998 when the City determines sewer connection is impractical.3 Submit the approved health department permit to the City before private-system construction.3 Smithville spans Clay and Platte Counties, so use the health department for the parcel’s county; Clay County parcels go to the Clay County Public Health Center’s Environmental Health program.45

Can you live in an RV or tiny home in Smithville?

We could not confirm a complete rule for living in an RV on an ordinary Smithville residential lot; ask Smithville Planning & Zoning about dwelling occupancy before buying an RV for temporary housing. Smithville’s conditional-use provisions for campgrounds in agricultural districts do not establish permission to occupy an RV as a dwelling on an ordinary residential lot.16

Smithville single-family dwellings in A-1 and R-1A must have at least 1,100 square feet of habitable floor area, excluding basements, garages, attics and other nonliving areas.78 Smithville allows accessory dwellings only in specified districts and requires the owner to occupy the main dwelling or accessory dwelling.9 An accessory dwelling needs a valid certificate of occupancy, renewed every 3 years.17 Do not assume an accessory-dwelling approval answers a tiny-home-on-wheels proposal; ask the city to classify the proposed dwelling.

Building a home in Smithville: what are the steps?

  1. Confirm city limits, the parcel’s county and zoning district with Smithville Planning & Zoning; Smithville zoning applies inside the city, and the private-sewage authority depends on the parcel’s county.24
  2. Resolve lot or plat issues before designing the house: Smithville’s subdivision regulations condition building permits and utility extensions on final plat approval, subject to stated exceptions.18
  3. Ask the City whether sewer connection is required; if a private system qualifies, obtain county health approval and submit the approved permit to the City before system construction.63
  4. Submit the city building permit application and obtain the building permit before work begins.1
  5. Arrange inspections with Smithville Building Inspections; the city requires advance notice for inspection requests.1

What should you check before buying Smithville land?

Ask Smithville Planning & Zoning about the proposed use, setbacks and plat status, and ask Building Inspections about driveway access, private wells and the current building permit fee schedule; we could not confirm complete city rules for those questions. For floodplain development in Missouri, a community floodplain permit is required, with an engineering No-Rise Certificate required before permitting development in a regulatory floodway.19 Ask the City to identify the applicable floodplain administrator for the parcel.

For county context, only 4.1% of Clay County soils are rated “not limited” for a conventional septic drain field; the county-wide rating calls for a parcel-specific evaluation and does not mean septic is impossible.20 For land outside Smithville city limits, use the Clay County guide: Clay County’s residential building permit requirements apply to unincorporated land.21

Watch-outs

  • A Smithville lot large enough for an R-1A dwelling is not automatically eligible for private sewage disposal: the city’s general septic threshold is 3 acres, subject to the older-platted-lot exception.123
  • Smithville’s septic authority depends on whether the parcel lies in Clay or Platte County; do not route every city parcel to Clay County.4
  • We could not confirm RV dwelling occupancy or a city owner-builder exemption; ask Smithville Planning & Zoning about RV occupancy and Building Inspections about owner-built construction.111

Sources

  1. Smithville Development Department — Building Inspections (smithvillemo.org)
  2. Code of Ordinances, City of Smithville, Missouri (Smithville), quoted and re-checked
  3. Chapter 700: Public and Private Sewers (Smithville), quoted and re-checked
  4. Chapter 700: Public and Private Sewers (Smithville), quoted and re-checked
  5. Clay County Public Health Center — Environmental Health (clayhealth.com)
  6. Chapter 700: Public and Private Sewers (Smithville), quoted and re-checked
  7. Division 1: Primary District Regulations (Smithville), quoted and re-checked
  8. Division 1: Primary District Regulations (Smithville), quoted and re-checked
  9. Division 4: Supplementary District Regulations (Smithville), quoted and re-checked
  10. Article I: Building Code Adoption (Smithville), quoted and re-checked
  11. Smithville Planning & Zoning Department (smithvillemo.org)
  12. Division 1: Primary District Regulations (Smithville), quoted and re-checked
  13. Division 1: Primary District Regulations (Smithville), quoted and re-checked
  14. Division 1: Primary District Regulations (Smithville), quoted and re-checked
  15. Division 1: Primary District Regulations (Smithville), quoted and re-checked
  16. Division 1: Primary District Regulations (Smithville), quoted and re-checked
  17. Division 4: Supplementary District Regulations (Smithville), quoted and re-checked
  18. Article I: General Provisions, Subdivision Regulations (Smithville), quoted and re-checked
  19. Floodplain Forms (Missouri statewide rule), quoted and re-checked
  20. Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data
  21. Residential Construction (2026 county census)

Written October 12, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.

Answers from the rulebook for Smithville

Smithville’s own rules

  • Building code adoptedAdopted

    Buildings and structures inside Smithville city limits

    • The adopted code is the 2018 International Building Code with City amendments in Section 500.025.
    • Separate residential, mechanical, plumbing, electrical, fuel-gas, energy, property-maintenance, and pool-code adoptions are addressed in Chapter 500.

    building code edition: 2018 International Building Code (with City amendments)

    “be and is hereby adopted as the Building Code of the City of Smithville”
  • Certificate of occupancyLimited

    Accessory dwelling units in Smithville zoning districts A-1, A-R, R-1A, R-1B, R-1C, R-1D, and B-4

    • An ADU may not be occupied without a valid certificate of occupancy.
    • ADUs must reapply for a new certificate of occupancy every three years, with owner certification of compliance.

    certificate renewal interval: 3 years

    “All ADU's must reapply for a new certificate of occupancy every three (3) years where the owner certifies compliance with the provisions herein.”
  • Local zoningPresent

    Land inside Smithville city limits; City Chapter 400 zoning regulations

    • District-specific permitted, conditional, and dimensional rules apply.
    “Permitted Uses. The following uses shall be permitted in "A-1" Districts:”
  • Zoning districtsPublished

    Land inside Smithville city limits

    • Published districts include A-1, A-R, R-1A, R-1B, R-1C, R-1D, R-1M, R-2, R-3, B-1, B-2, B-3, B-4, I-1, and I-2, plus overlay and supplementary regulations.
    “Section 400.100 "R-1A" Single-Family Suburban Dwelling District Use Regulations.”
  • Camping on your landLimited

    Campgrounds and similar recreational uses in the A-1 Agricultural and A-R Agricultural-Residential districts

    • A conditional use permit under Section 400.570 is required.
    • This claim does not establish unrestricted camping or RV dwelling occupancy on ordinary residential lots.
    “Recreational and entertainment uses, including athletic fields, campgrounds, golf courses and driving ranges, riding stables, and zoos.”
  • Accessory dwellingsLimited

    Accessory dwelling units inside Smithville city limits

    • Only authorized in A-1, A-R, R-1A, R-1B, R-1C, R-1D, or B-4 districts.
    • Only one ADU per lot or parcel.
    • The owner must occupy either the principal structure or ADU.
    • Maximum ADU occupancy is two unrelated adults.
    • Minimum rental term is 30 days.
    • A valid certificate of occupancy is required and must be renewed every three years.

    maximum ADUs: 1 per lot or parcel · minimum rental term: >= 30 days · maximum unrelated adult occupants: <= 2 adults

    “May only be authorized if located on land within zoning districts A-1, A-R, R-1A, R-1B, R-1C, R-1D or B-4.”
  • Mandatory utility hookupSewer (with conditions)

    A new building inside Smithville city limits that City plumbing or building codes require to connect to a sewer

    • A public sewer is available when the sewer main is within 100 feet of the subject property's property line.
    • The alternative private system must be approved by the county Health Department and generally requires at least three acres, subject to the pre-October 20, 1998 platted-lot exception.
    • The City may determine that connection is impractical due to distance, obstacles, cost, or other considerations.

    public sewer availability distance: <= 100 feet from property line

    “A public sewer is available if the sewer main is located within one hundred (100) feet of a property line of the subject property.”
  • Subdividing landRegulated (with conditions)

    Subdivision of land into two or more parts within Smithville corporate limits

    • Exemptions include certain prior legal subdivisions, inheritance/probate/court divisions, public street-widening acquisitions, and specified leasehold divisions.
    • The City will not extend utilities, provide public-road access, or issue building permits for property lacking final plat approval, except as provided by the regulations.
    • Plats must conform to the zoning ordinance and required zoning changes or variances must occur before final-plat approval.
    “shall comply with the provisions of these regulations, unless otherwise exempted pursuant to this Section.”
  • Short-term rentalsLimited

    Short-term rentals inside Smithville city limits

    • A short-term-rental permit is required for each unit.
    • Annual inspection and approval are required, subject to the initial 60-day grace rule for lawful existing rentals.
    • Annual permit fee is $50.
    • Total permits are capped at no more than 3% of the City's housing stock, with additional block-face and apartment-density limits.
    • Business and occupation licensing, safety, insurance, tax, refuse, noise-management, and application requirements also apply.

    maximum total permits: <= 3 percent of total housing stock · annual permit fee: 50 USD · initial existing-rental grace period: 60 days (lawful short-term rentals existing before Chapter adoption)

    “A short-term rental permit is required for each such unit located within the City of Smithville.”

Rules another office applies inside Smithville

Smithville does not set these itself; the county, a health district or the state does, and they apply to every address inside its limits.

  • Minimum dwelling sizeSpecified

    Single-family dwellings in Smithville A-1 Agricultural District

    • Basements, garages, attics, and other areas not designed for living space are excluded.

    minimum habitable floor area: >= 1100 square feet (excluding basements, garages, attics and other areas not designed for living space)

    “Single-family dwellings shall have a minimum of one thousand one hundred (1,100) square feet of habitable floor area”
    One more reviewed finding on this topic
    • Specified — Single-family dwellings in Smithville R-1A Single-Family Suburban Dwelling District
      “Single-family dwellings shall have a minimum of one thousand one hundred (1,100) square feet of habitable floor area”
  • Minimum lot sizeSpecified

    R-1A Single-Family Suburban Dwelling District

    minimum lot area: >= 10000 square feet

    “The minimum lot area shall be ten thousand (10,000) square feet.”
  • SetbacksSpecified

    A-1 Agricultural District

    • Front setback depends on road classification.
    • Double-frontage lots require a front yard on each street.
    • Corner lots require front setbacks along both abutting streets, subject to the stated reduction exception.
    • Side-yard minimum is 10 feet; rear-yard minimum is 20 feet.

    front yard, local road: 55 feet from street centerline · front yard, collector road: 60 feet from street centerline · front yard, arterial road: 70 feet from street centerline · front yard, arterial over three lanes: 30 feet from edge of right-of-way · side yard: >= 10 feet · rear yard: >= 20 feet

    “Local: fifty-five (55) feet measured from the centerline of the street.”
    One more reviewed finding on this topic
    • Specified — R-1A Single-Family Suburban Dwelling District
      “Side Yard Area. The side yard area shall be not less than seven and one-half (7.5) feet.”
  • Lot coverageSpecified

    R-1A Single-Family Suburban Dwelling District

    maximum lot coverage: <= 30 percent of total lot area

    “The maximum lot coverage shall be thirty percent (30%) of the total lot area.”
  • Building heightSpecified

    Dwellings in A-1 Agricultural District

    • Farm structures have no height limitations under the cited district rule.
    • The supplementary height rule provides two additional feet of height for each one foot of additional setback on all sides over the minimum.

    maximum dwelling structure height: <= 35 feet (farm structures have no height limitations)

    “The maximum structure height is thirty-five (35) feet for dwellings; farm structures have no height limitations.”
    One more reviewed finding on this topic
  • Who permits septicCounty (with conditions)

    Private sewage disposal systems for property inside Smithville city limits in the county where the property lies

    • The City code identifies the relevant county Health Department as the permitting authority; Smithville spans Clay and Platte Counties.
    • The exact county authority varies by the parcel's county.
    “installed in accordance with or subject to a permit from the Clay County Health Department.”
  • Septic permitRequired

    A private sewage disposal system serving property inside Smithville city limits

    • Plans and specifications must be submitted to and approved by the County Health Department for the county where the property lies.
    • The lot must be at least three acres, or smaller only if platted before October 20, 1998 and public sewer connection is impractical as determined by the City.
    • Before construction, the owner must submit a copy of the approved Health Department permit to the City.

    public sewer availability distance: <= 100 feet from property line · minimum lot area for private sewage disposal: >= 3 acres (smaller pre-October 20, 1998 platted lots may qualify when sewer connection is impractical)

    “Prior to construction of a private sewage disposal system, the properly owner must submit a copy of the approved permit from the relevant Health Department to the City.”
  • Off-grid sanitationLimited

    Private sewage disposal systems used instead of public sewer inside Smithville city limits

    • Requires County Health Department approval and permit.
    • The City code generally requires at least three acres, with a limited exception for smaller lots platted before October 20, 1998 when sewer connection is impractical.
    • The approved permit must be submitted to the City before construction.
    “Construct a private sewage disposal system in accordance with the plans and specifications submitted to and approved by the County Health Department”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Smithville or Clay County directly.

  • Building permit — Building construction inside Smithville city limits
  • Owner-builder exemption — Owner-builders constructing inside Smithville city limits
  • Inspections — Building construction inside Smithville city limits
  • Living in an RV — Occupancy of recreational vehicles as a dwelling inside Smithville city limits
  • Tiny homes — Tiny-home occupancy inside Smithville city limits
7 more unanswered
  • Manufactured homes
  • Septic inspection
  • Well permit
  • Agricultural exemption
  • Driveway access
  • Permit fees
  • Permit process

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Unanswered questions are usually a sign that Smithville publishes no rule on the point, not that none exists. Clay County’s page lists the county offices to call.

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