Bolthole Index

Jefferson County, Missouri

Building permits, zoning and septic rules in De Soto, Missouri

De Soto, Missouri requires city building permits for new residential construction and runs its own zoning inside city limits in Jefferson County.12 De Soto also requires sewer connection for qualifying homes near a public sewer.3 For an onsite septic system, confirm jurisdiction with Jefferson County Code Enforcement and Missouri DHSS, because some incorporated areas fall outside the county ordinance.4

At a glance

Building permits
City building permit required for new construction; online applications through Cloud Permit1
Zoning
City zoning districts control uses and dimensional standards25
Sewer and septic
Qualifying homes must connect to public sewer; confirm onsite permitting authority for a city address34
New-home building permit fee
Residential living space: $0.44 per square foot6
Agricultural district lot size
A-1 minimum lot area: 5 acres for any use7
RV and tiny-home living
We could not confirm city occupancy rules; ask the Building Inspector and Planning and Zoning before buying89
House-sale occupancy
Certificate of occupancy follows inspection and compliance; occupancy permit fee is $3010

Who to call

Building permits

City of De Soto Building Inspector

City building-permit applications; City Hall contact for the Building Inspector.

636-586-3326

17 Boyd Street

Online permits →

Planning & zoning

City of De Soto Planning and Zoning

City Hall contact for Planning and Zoning questions.

636-586-3326

17 Boyd Street

Codes & inspections

City of De Soto Building Department — Project Requirements

Residential construction requirements and house-sale inspections.

Septic permits

Missouri DHSS Onsite Wastewater Treatment Program

State onsite program and Jefferson County jurisdiction lookup; confirm whether a De Soto address is covered by the county ordinance or referred to DHSS.

573-751-6095

[email protected]

PO Box 570

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 De Soto means bringing your own water and power. The kit we’d start with:

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Do you need a building permit in De Soto, MO?

De Soto requires a city building permit for new residential and commercial construction, and accepts applications through Cloud Permit.1 The city also lists storage buildings and retaining walls of any size among work requiring a building permit, so a small outbuilding is not automatically exempt.8 Replacement or installation of framing, plumbing or electrical work requires approval under the city's published project requirements.11

De Soto has adopted the International Building Code, 2021 Edition, with local amendments.12 We could not confirm a city owner-builder or agricultural-building exemption; ask the Building Inspector about the proposed work before relying on either.8

Who issues De Soto building permits, and what do they cost?

Start with the De Soto Building Inspector through City Hall at 636-586-3326 or visit 17 Boyd Street; the city building-permit page links to Cloud Permit for online submission.8 New construction or major renovation normally requires sealed drawings from an architect or engineer, so discuss the plan requirements before commissioning drawings.1

De Soto's published residential building-permit fees are $0.44 per square foot of living space for new construction and $0.25 per square foot for remodeling living space.6 The city lists a $50 minimum for other building permits, including fences and decks.6 These are city charges; ask the Building Inspector to calculate the fee for the actual scope of work.68

Does De Soto have zoning, lot-size rules and setbacks?

De Soto has city zoning, with district-specific rules governing uses, lot dimensions, yards, lot coverage and height.25 Identify the parcel's city district with Planning and Zoning before choosing a house layout or assuming agricultural use is allowed.59

In De Soto's A-1 Agricultural Activities District, the minimum lot area for any use is 5 acres; that is a district rule, not a citywide minimum for every residential lot.7 In the R-1 One-Family Dwelling District, buildings or structures may cover no more than 30% of the lot.13 We could not confirm a complete A-1 setback schedule or a minimum dwelling floor area; ask city Planning and Zoning for the applicable dimensions before buying a narrow or irregular parcel.9

How do sewer connections and septic permits work inside De Soto?

De Soto requires owners of real estate used for human habitation to connect to public sewer when the property is adjacent to and within 150 feet of a public right-of-way containing a public sewer system.3 Connection is required within 120 days after sewer service becomes available to the property.3 Establish whether that requirement applies before budgeting for an independent septic system.3

Missouri requires a construction permit before installing or repairing most onsite wastewater systems, unless the appropriate authority confirms an exemption.14 The DHSS Jefferson County lookup names County Code Enforcement at (636) 797-5310 but warns that some incorporated areas are referred back to DHSS; we could not confirm which route applies to a De Soto parcel.4 Ask County Code Enforcement to confirm coverage, then contact the DHSS onsite program if the county defers the application.4

Can you live in an RV or tiny home on land in De Soto?

We could not confirm De Soto's rules for long-term RV occupancy, temporary camping, tiny-home occupancy or a separate accessory dwelling; ask the city Building Inspector and Planning and Zoning about the exact proposal before purchasing land.89 Request an answer for the parcel's district, the dwelling type and whether occupancy would be temporary during construction.59

De Soto's mobile-home-park sanitation rule requires discharge to public sanitary sewer when available, or a suitable treatment device approved by the Division of Health and the city when sewer is unavailable.15 That provision applies to mobile-home parks and does not establish permission to live in an RV on an individual lot.15

Building a home in De Soto: what should you do first?

  1. Confirm the city zoning district and ask Planning and Zoning for the permitted use and parcel dimensions before finalizing the site plan.59
  2. Determine whether the De Soto sewer-connection requirement applies; if onsite treatment is proposed, confirm jurisdiction with County Code Enforcement or DHSS before starting wastewater work.3144
  3. Ask the Building Inspector about construction documents, arrange sealed drawings where required, and submit the city building-permit application through Cloud Permit.1
  4. For development in the areas covered by De Soto's floodplain chapter, obtain the separate floodplain development approval before work begins; the City Manager administers that chapter.16

For an existing house being sold, De Soto issues the certificate of occupancy after inspection and satisfaction of the specified code requirements, so include that city step in purchase planning.10

What should you check before buying land in De Soto?

Ask De Soto Planning and Zoning about the district and any planned lot division: the city regulates subdivision approval, design standards and improvement assurances.517 Ask the City Manager whether the proposed development falls within the city floodplain chapter, which requires a separate development permit in covered areas, including for manufactured homes.16

For a private well, Missouri's installation rules require permits for regulated contractors but allow landowners to install their own well or pump under the applicable law and rules; we could not confirm additional city requirements.18 Ask the city Building Inspector about the proposed water supply and driveway access.8 For land outside city limits, use the Jefferson County guide for the county's unincorporated-area zoning answer rather than applying De Soto's city rules.19

Watch-outs

  • De Soto's sewer-connection rule can require public sewer even when a buyer prefers onsite wastewater treatment.3
  • We could not confirm permission for RV or tiny-home occupancy inside De Soto; ask city Planning and Zoning and the Building Inspector before committing to that use.98
  • De Soto requires a separate floodplain development permit for covered development; a city building-permit application does not replace that approval.16
  • A De Soto house sale requires inspection and compliance before the city issues its certificate of occupancy.10

Sources

  1. Building Permit (De Soto), quoted and re-checked
  2. Table of Contents - City of De Soto, MO (De Soto), quoted and re-checked
  3. Section 710.160 and Section 710.190 Sewer Connections (De Soto), quoted and re-checked
  4. Missouri DHSS Onsite Wastewater Treatment Program (health.mo.gov)
  5. Chapter 405 Zoning Regulations (De Soto), quoted and re-checked
  6. Building Permit Fees (De Soto), quoted and re-checked
  7. Article III: Zoning Districts-Use and Regulations (De Soto), quoted and re-checked
  8. City of De Soto Building Inspector (desotomo.com)
  9. City of De Soto Planning and Zoning (desotomo.com)
  10. Project & Permit Requirements (De Soto), quoted and re-checked
  11. City of De Soto Building Department — Project Requirements (desotomo.com)
  12. Chapter 500 Building Codes and Building Regulations (De Soto), quoted and re-checked
  13. Article III: Zoning Districts-Use and Regulations (De Soto), quoted and re-checked
  14. OWTS Construction Permit Process (Missouri statewide rule), quoted and re-checked
  15. Chapter 415 Mobile Homes and Mobile Home Parks (De Soto), quoted and re-checked
  16. Article III: Administration - Floodplain Management (De Soto), quoted and re-checked
  17. Chapter 410 Subdivision Regulations (De Soto), quoted and re-checked
  18. Water Wells - PUB2945 (Missouri statewide rule), quoted and re-checked
  19. jeffcomo.gov (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 De Soto

De Soto’s own rules

  • Building code adoptedAdopted

    Building construction inside De Soto city limits.

    • The adopted code is subject to the amendments in Chapter 500.

    edition: International Building Code, 2021 Edition

    “The "International Building Code, 2021 Edition" as published by the International Code Council is hereby adopted as the Building Code of the City of De Soto, Missouri, regulating and governing the conditions and maintenance of all property, buildings and structures;”
  • InspectionsLimited

    A house being sold inside De Soto city limits.

    • The inspection must be finished before the certificate of occupancy is issued.
    • The requirements include the 2021 International Property Maintenance Code and 2006 NFPA Life Safety Code.
    “A Certificate of Occupancy for a house being sold shall be issued after the inspection is finished and all requirements have been met regarding the 2021 International Property Maintenance Code and 2006 NFPA Life Safety Code.”
  • Certificate of occupancyLimited

    A house being sold inside De Soto city limits.

    • Issuance follows completion of inspection and satisfaction of the listed code requirements.

    occupancy permit fee: 30 USD

    “A Certificate of Occupancy for a house being sold shall be issued after the inspection is finished and all requirements have been met regarding the 2021 International Property Maintenance Code and 2006 NFPA Life Safety Code.”
  • Local zoningPresent

    Land inside De Soto city limits.

    • Chapter 405 establishes city zoning districts and regulations.
    “Title IV Land Use [...] Chapter 405 Zoning Regulations [...] Chapter 410 Subdivision Regulations”
  • Zoning districtsPublished

    Zoning districts inside De Soto city limits.

    • The published district provisions include A-1, R-1, R-2, R-3, R-4, commercial, manufacturing, and PUD districts.
    • District-specific regulations control uses, lot dimensions, yards, coverage, and height.
    “Section 405.100 "A-1" Agricultural Activities District Regulations. [...] Section 405.110 "R-1" One-Family Dwelling District Regulations. [...] Section 405.120 "R-2" One-Family Dwelling District Regulations. [...] Section 405.140 "R-4" Multiple-Family District Regulations.”
  • Minimum lot sizeSpecified

    A-1 Agricultural Activities District inside De Soto city limits.

    • The A-1 section states that minimum lot area for any use is five acres.

    minimum lot area: >= 5 acres

    “Lot size (area). Minimum lot area for any use shall be five (5) acres.”
  • Lot coverageSpecified

    R-1 One-Family Dwelling District inside De Soto city limits.

    maximum lot coverage by buildings or structures: <= 30 percent

    “The maximum lot coverage by buildings or structures shall not exceed thirty percent (30%) of the lot area.”
  • Off-grid sanitationLimited

    Mobile home parks inside De Soto city limits where a public sanitary sewer is unavailable.

    • If a public sanitary sewer is available, sewage must be discharged into it.
    • If unavailable, a suitable sewage treatment device must be constructed and operated in a manner approved by the Division of Health and the City.
    “Adequate disposal of sewage shall be provided by discharge into a public sanitary sewer, provided a public sanitary sewer is now or shall hereafter be available, but no ordinance or regulation regarding sewer connection and charges therefor is hereby repealed. If a public sanitary sewer is not available, disposal shall be by discharge into a suitable sewage treatment device, such sewage treatment device to be constructed and operated in a manner approved by the Division of Health and the City.”
  • Mandatory utility hookupSewer (with conditions)

    Real estate used for human habitation inside De Soto city limits and adjacent to and within 150 feet of a public right-of-way where a public sewer system is located.

    • Connection is required within 120 days after sewers are made available.
    • Non-compliance can result in notice, water shutoff, and meter removal.
    • The reviewed source does not establish a general mandatory public-water connection rule.

    distance from public right-of-way: <= 150 feet · connection deadline after sewer availability: 120 days

    “It shall be the duty of each owner of real estate used for human habitation and located adjacent to and within one hundred fifty (150) feet of a public right-of-way where a public sewer system is located to make proper connection with such sewer. Non-compliance with the provisions of this Section shall be punishable as a misdemeanor, and the property owners shall be liable for sewer service charges, although not connected to the sewers. Property owners shall have one hundred twenty (120) days to connect to sewers after sewers are made available to the property.”
  • Subdividing landRegulated (with conditions)

    Subdivision activity inside De Soto city limits.

    • Chapter 410 includes subdivision-approval procedures, design standards, improvement assurances, and enforcement provisions.
    “Chapter 410 Subdivision Regulations [...] Article II Procedures For Subdivision Approval [...] Article III Subdivision Design Standards [...] Article V Administration and Enforcement”
  • Building in a floodplainRequired

    Proposed construction or other development in the areas covered by De Soto's floodplain chapter.

    • A separate floodplain development permit is required for each structure or other development.
    • The requirement includes placement of manufactured homes.
    • The City Manager administers the chapter.
    “A floodplain development permit shall be required for all proposed construction or other development, including the placement of manufactured homes, in the areas described in Article II, Section 420.040. No person, firm, corporation, or unit of government shall initiate any development or substantial improvement or cause the same to be done without first obtaining a separate floodplain development permit for each structure or other development.”
  • Permit feesPublished

    City building and occupancy permits inside De Soto city limits.

    • The city page states the fees are outlined in the city code.

    residential new construction living space: 0.44 USD per square foot · residential remodeling living space: 0.25 USD per square foot · other permits minimum: 50 USD (Fence, deck, etc.) · occupancy permit: 30 USD · re-inspection after 10: 30 USD

    “Residential New Construction – Living Space | $0.44 PSF [...] All other permits (minimum) (Fence, Deck Etc.) | $50.00 [...] Occupancy Permit | $30.00”
  • Permit processPublished

    City building-permit applications inside De Soto city limits.

    • Building permits may be submitted online through the Cloud Permit Website.
    • New construction or major renovation normally requires sealed drawings from an architect or engineer.
    • The city instructs applicants to contact the Building Department when uncertain.
    “Building permits may be submitted online through the Cloud Permit Website. A building permit is required for, but not limited to, the following: New construction (residential and commercial)”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask De Soto or Jefferson County directly.

  • Owner-builder exemption — Owner-builder exemption from De Soto city building requirements.
  • Minimum dwelling size — Single-family residential development inside De Soto city limits.
  • Setbacks — A-1 Agricultural Activities District inside De Soto city limits.
  • Living in an RV — Long-term recreational-vehicle occupancy on private land inside De Soto city limits.
  • Camping on your land — Temporary camping on private land inside De Soto city limits.
6 more unanswered
  • Tiny homes
  • Accessory dwellings
  • Well permit
  • Agricultural exemption
  • Driveway access
  • Short-term rentals

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 De Soto publishes no rule on the point, not that none exists. Jefferson County’s page lists the county offices to call.

← All of Jefferson County: county rules, score and offices