Bolthole Index

Lincoln County, Missouri

Building permits, zoning and septic rules in Troy, Missouri

Troy, Missouri requires a city building permit before constructing or altering a building inside city limits.1 Troy sets its own zoning, while the Lincoln County Health Department handles covered septic installations and major repairs.23 Public sewer connection is mandatory for qualifying Troy properties, so septic is not automatically an alternative to city sewer.4

At a glance

Building permits
Required through the city Building Commissioner for construction and alterations1
Zoning
City zoning applies; confirm the parcel on the Official Zoning Map at City Hall25
Septic permits
Lincoln County Health Department handles covered new installations and major repairs36
Public sewer
Qualifying properties must connect when public sewer is within 100 feet of the property line4
Minimum home size
R-1: 1,000 square feet above grade for single-family lots and subdivisions approved after July 17, 20007
Accessory dwellings
The general zoning rule prohibits using an accessory building as a dwelling8

Who to call

Building permits

City of Troy Building Department

Building-office questions and access to applications and inspection results

636-528-1254

[email protected]

Online permits →

Codes & inspections

City of Troy Building Commissioner

City building-permit applications, plans and certificates of occupancy

Septic permits

Lincoln County Health Department, Environmental Health

Covered onsite wastewater construction permits and inspections for new installations and major repairs

(636)528-6117

5 Health Department Drive, Troy, MO, 63379

Floodplain permits

Lincoln County Floodplain Office

Flood-zone questions; ask Troy to confirm the permitting administrator for land inside city limits

636-528-6182

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

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Do you need a building permit in Troy, MO?

Troy requires a building permit from the city Building Commissioner before erecting, reconstructing, converting, altering, enlarging or moving a building or structure.1 Troy has adopted the 2015 International Building Code with local revisions.9 Ask the City of Troy Building Department to identify the applicable requirements for your proposed home, addition or conversion.10

Outside Troy city limits, Lincoln County does not require county-issued building permits in unincorporated areas; use the Lincoln County guide for that separate answer.11 The county exemption does not replace Troy’s city building-permit requirement.111

Who handles Troy building-permit applications?

The City of Troy Building Department’s public portal lists 636-528-1254 and [email protected] for support, and provides access to applications and inspection results.10 Troy’s adopted code directs written building-permit applications to the Building Commissioner, accompanied by detailed plans in duplicate showing building size, location on the lot, materials and construction details.1

Before preparing a submission, ask the Building Department for the current application, fee schedule and required inspection list.10 Troy’s code also says a new building cannot be occupied until the Building Commissioner issues a certificate of occupancy; include that approval in your move-in planning.1

Does Troy have zoning, minimum lot sizes and setbacks?

Troy zoning applies throughout the city’s corporate limits, and the Official Zoning Map at City Hall is the final authority for a parcel’s current zoning status.25 In R-1, a single-family lot generally needs 10,000 square feet and 80 feet of average width, with exceptions for qualifying existing recorded or separately owned substandard lots.12 In R-2, the stated minimums are 8,000 square feet and 70 feet of average width.13

R-1 setbacks are 30 feet at the front, 8 feet on each side and 30 feet at the rear, subject to the code’s modifications; R-2 uses the same yard rules.1415 Confirm district and applicable exceptions before choosing a house footprint.514

How do sewer connections and septic permits work in Troy?

For occupied or used Troy properties abutting a street or right-of-way containing public sanitary sewer within 100 feet of the property line, the city requires connection at the owner’s expense within 90 days after official notice.4 The code separately requires connection within 60 days when public sewer becomes available, followed by cleaning and filling the private system.4

Where private sewage disposal is used, most installations or repairs need a septic construction permit; confirm any exemption before work begins.16 Lincoln County Health Department handles covered permits and inspects new installations and major repairs.36 Only 4% of Lincoln County soils are rated not limited for conventional drain fields; this countywide rating supports a site evaluation, not a conclusion that septic is impossible on a Troy lot.17

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

We could not confirm Troy’s general rules for residential RV occupancy, temporary camping or tiny-home occupancy; ask the City of Troy Building Department about the proposed use and parcel before buying a vehicle or structure.10 Troy’s general accessory-building rule prohibits dwelling use and prohibits constructing an accessory building before construction of the main building has actually commenced.8

For R-1 subdivisions and single-family lots approved for development after July 17, 2000, dwellings need at least 1,000 square feet of livable floor space completely above grade, excluding garages and space over open porches.7 A small structure therefore needs a district-specific review rather than an assumption that tiny-home living is allowed.75

What are the steps to building a home in Troy?

  1. Confirm the parcel’s city zoning against the Official Zoning Map at City Hall, then check district lot-size and setback requirements.512131415
  2. Establish whether the property must connect to public sewer; where septic is appropriate, obtain the required approval or confirm an exemption before installation.416
  3. Submit the written city building-permit application and detailed plans, and obtain the building permit before construction begins.1
  4. Ask the Building Department for the project’s inspection schedule and obtain the required certificate of occupancy before occupying the new building.101

What should you check before buying land in Troy?

Ask the Lincoln County Floodplain Office about the property’s flood zone, then ask Troy’s Building Department to identify the applicable municipal floodplain permitting administrator.1810 Missouri requires a permit for all development in a floodplain, and regulatory-floodway development requires an engineering No-Rise Certificate before the community can issue the floodplain development permit.19

A driveway constructed or modified within MoDOT right-of-way needs a MoDOT permit; that statewide rule does not establish the answer for city streets.20 We could not confirm Troy-specific private-well approval or owner-builder exemptions; ask the Building Department before relying on either.10 If you plan to divide land, Troy’s subdivision regulations include preliminary and final plat procedures and improvement standards.21

Watch-outs

  • Troy’s city building-permit and zoning requirements apply inside city limits; Lincoln County’s unincorporated-area building-permit exemption does not answer a Troy parcel’s requirements.1211
  • Public sewer availability can require a Troy property to connect and abandon a private wastewater system.4
  • Missouri temporarily suspended application fees under the DHSS onsite wastewater program effective August 28, 2026, but local-authority processes may vary; ask Lincoln County Health Department for the current local septic charge.2223

Sources

  1. City of Troy Building Commissioner (ecode360.com)
  2. City of Troy, MO Title, Purpose, Scope and Legality (Troy), quoted and re-checked
  3. On-site Septic Systems and Subdivisions, quoted and re-checked
  4. Chapter 705: Sewer System - City of Troy, MO (Troy), quoted and re-checked
  5. City of Troy, MO Zoning District Boundaries and Maps (Troy), quoted and re-checked
  6. Wastewater Treatment Systems — Lincoln County Health Department (Troy), quoted and re-checked
  7. Article IV: District Regulations - City of Troy, MO (Troy), quoted and re-checked
  8. Article VI: Supplementary District Regulations - City of Troy, MO (Troy), quoted and re-checked
  9. Chapter 500: Building Regulations - City of Troy, MO (Troy), quoted and re-checked
  10. City of Troy Building Department (ci-troy-mo.smartgovcommunity.com)
  11. Planning and Zoning in Lincoln County, Missouri, quoted and re-checked
  12. Article IV: District Regulations - City of Troy, MO (Troy), quoted and re-checked
  13. Article IV: District Regulations - City of Troy, MO (Troy), quoted and re-checked
  14. Article IV: District Regulations - City of Troy, MO (Troy), quoted and re-checked
  15. Article IV: District Regulations - City of Troy, MO (Troy), quoted and re-checked
  16. OWTS Construction Permit Process (Troy), quoted and re-checked
  17. 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
  18. Lincoln County Floodplain Office (lincolncomo.gov)
  19. Floodplain Forms (Missouri statewide rule), quoted and re-checked
  20. Permits | Missouri Department of Transportation (Missouri statewide rule), quoted and re-checked
  21. Chapter 410: Subdivision Regulations - City of Troy, MO (Troy), quoted and re-checked
  22. OWTS Construction Permit Process (Missouri statewide rule), quoted and re-checked
  23. Lincoln County Health Department, Environmental Health (lchdmo.org)

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 Troy

Troy’s own rules

  • Building code adoptedAdopted

    Building regulation inside Troy city limits.

    • The adopted code is the 2015 International Building Code; the ordinance refers to copies on file with the Building Official and includes local revisions.

    building code edition: 2015 International Building Code

    “International Building Code, 2015 Edition, as published by the International Code Council, be and is hereby adopted as the Building Code of the City of Troy”
  • Local zoningPresent

    All land, property and development within Troy city's existing and future corporate limits.

    • The zoning chapter establishes minimum regulations; parcel zoning must be confirmed against the Official Zoning Map at City Hall.
    “The regulations established by this Chapter shall apply to all land, property and development within the existing and future corporate limits of the City of Troy.”
  • Zoning districtsPublished

    Zoning districts inside Troy city limits.

    • The Official Zoning Map at City Hall is the final authority for the current zoning status of a parcel.
    “The Official Zoning Map shall be located in City Hall and shall be available to the public and shall along with the Zoning Ordinance be the final authority as to the current zoning status of any parcel, lot, district, use, building or structure in the City.”
  • Accessory dwellingsProhibited

    Use of an accessory building for dwelling purposes inside Troy city limits.

    • The zoning chapter separately lists some accessory uses and guest houses in R-1; this claim concerns the cited general accessory-building rule.
    “No accessory building shall be constructed upon a lot until the construction of the main building has been actually commenced, and no accessory building shall be used for dwelling purposes.”
  • Mandatory utility hookupSewer (with conditions)

    Houses, buildings, and other occupied or used properties inside Troy city limits that abut a street or right-of-way containing a public sanitary sewer within 100 feet of the property line.

    • Connection is at the owner's expense.
    • Connection must occur within 90 days after official notice.
    • When a public sewer becomes available, the building sewer must be connected within 60 days and the private system must be cleaned and filled.

    public sewer distance from property line: <= 100 feet · connection deadline after official notice: 90 days · connection deadline when public sewer becomes available: 60 days

    “is hereby required at his/her expense to install suitable toilet facilities therein and to connect such facilities directly with the proper public sewer in accordance with the provisions of this Chapter, within ninety (90) days after date of official notice to do so, provided that said public sewer is within one hundred (100) feet (thirty point five {30.5} meters) of the property line.”
  • Subdividing landRegulated (with conditions)

    Land subdivision inside Troy city limits.

    • The chapter establishes preliminary and final plat requirements, physical-improvement standards, open-space requirements, and related procedures.
    “This Chapter shall be known, referred to and cited as "The Land Subdivision Code of Troy, Missouri".”

Rules another office applies inside Troy

Troy 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 the R-1 Single-Family Residential District.

    • Applies to subdivisions and single-family lots approved for development after July 17, 2000.
    • The floor space must be livable, completely above grade, and excludes garage space and area over open porches.

    minimum livable floor area: >= 1000 square feet (Completely above grade; excludes garage space and area over open porches.) · development approval date threshold: > 2000-07-17

    “For all subdivisions and single-family lots approved for development after July 17, 2000, all dwellings shall contain a minimum of one thousand (1,000) square feet of livable floor space completely above grade. This space shall be exclusive of garage space and area over open porches.”
  • Minimum lot sizeSpecified

    Single-family lots in the R-1 Single-Family Residential District.

    • A recorded lot or tract existing on the effective date of the chapter may be used despite the stated area and width limits.
    • A separately owned substandard lot may be occupied by a single-family dwelling or other permitted use.

    minimum lot area: >= 10000 square feet (Recorded lots existing on the effective date may be used if under the minimum.) · minimum average lot width: >= 80 feet (Recorded lots existing on the effective date may be used if under the minimum.)

    “A lot occupied by a single-family dwelling shall contain not less than ten thousand (10,000) square feet and shall be not less than eighty (80) feet in width (average width — back and front total divided by two (2)).”
    One more reviewed finding on this topic
    • Specified — Single-family lots in the R-2 Single-Family Residential District.
      “A lot occupied by a single-family dwelling shall contain not less than eight thousand (8,000) square feet and shall be not less than seventy (70) feet in width (average width — back and front total divided by two (2)).”
  • SetbacksSpecified

    R-1 Single-Family Residential District.

    • The code states that yard regulations are subject to modifications in Section 405.190.
    • The district table gives front, side, and rear setbacks.

    front yard setback: >= 30 feet (Subject to Section 405.190.) · side yard setback each side: >= 8 feet (Subject to Section 405.190.) · rear yard setback: >= 30 feet (Subject to Section 405.190.)

    “Front yard. There shall be a front yard of not less than thirty (30) feet. Side yard. There shall be a side yard on each side of a lot of not less than eight (8) feet. Rear yard. There shall be a rear yard of not less than thirty (30) feet.”
    One more reviewed finding on this topic
  • Building heightDistrict specific (with conditions)

    R-1 and R-2 residential districts.

    • The code provides exceptions in Section 405.190.
    • The stated limit is two and one-half stories and 35 feet.

    maximum building height: <= 35 feet (Except as provided in Section 405.190.) · maximum stories: <= 2.5 stories (Except as provided in Section 405.190.)

    “No building shall exceed two and one-half (2½) stories, nor shall it exceed thirty-five (35) feet in height except as provided in Section 405.190.”
  • Septic permitRequired

    Most onsite wastewater treatment system installations or repairs inside Troy city limits where private sewage disposal is used.

    • Some single-family residential lots may be exempt.
    • The appropriate permitting authority must be determined for the specific work location.
    • Work should not begin until a permit is issued or an exemption is confirmed.
    “A construction permit is required before installing or repairing most onsite wastewater treatment systems (OWTS). Some single family residential lots may be exempt from permitting.”
  • Septic inspectionRequired

    New septic installations and major repairs requiring permits through the Lincoln County Health Department inside Troy city limits.

    • The county page does not state that every existing septic system receives periodic inspection.
    “Lincoln County Health Department inspects new installations and major repairs that require permitting through our office.”

Still unanswered

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

  • Owner-builder exemption — Owner-builder exemptions from Troy building-permit requirements.
  • Inspections — Building inspections inside Troy city limits.
  • Certificate of occupancy — Certificates of occupancy for buildings inside Troy city limits.
  • Lot coverage — Lot coverage inside Troy city limits.
  • Living in an RV — Residential or long-term recreational-vehicle occupancy on private land inside Troy city limits.
7 more unanswered
  • Camping on your land
  • Tiny homes
  • Well permit
  • Agricultural exemption
  • Driveway access
  • Short-term rentals
  • Permit fees

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

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