Bolthole Index

Natrona County, Wyoming

Zoning, building permits and septic rules in Evansville, Wyoming

The Town of Evansville, Natrona County, Wyoming has its own zoning ordinance and requires a building permit from the town for new construction inside town limits12. Septic permits are a separate matter: the Casper-Natrona County Health Department permits septic systems in all areas of Natrona County3. Natrona County's own rules cover only unincorporated land outside town limits4.

At a glance

Building permit
Required from the town for building, altering, moving or converting a structure2
Zoning
Town zoning ordinance applies to private land inside town limits1
Building codes
Permits are reviewed against the IBC and IRC5
R-1 minimum lot
7,000 square feet6
R-1 setbacks
25 feet front, 5 feet side7
Septic
Casper-Natrona County Health Department permits septic systems countywide3
Wells
State well permit required before drilling8
Certificate of occupancy
Required before a new building is used or occupied9

Who to call

Building permits

Town of Evansville (town hall, building department and zoning)

Zoning certificates, building permits and certificates of occupancy inside town limits

307-234-6530

235 Curtis St, Evansville, WY 82636

Septic permits

Casper-Natrona County Health Department, Environmental Health Division

Permitting, installation oversight and use of onsite wastewater treatment systems

307-235-9340

1017 S Conwell St., Casper, WY 82601

Contact details are copied from each office’s official page and were checked against it on October 24, 2026.

Off-grid gear

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

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Does Evansville, Wyoming have zoning?

Yes. Evansville's zoning ordinance applies to all private land inside the town's corporate limits1. The ordinance sets up residential districts R-1, R-2, R-3, R-4 (manufactured home) and UA (urban agriculture), plus commercial and industrial districts, and the official zoning map is kept at town hall10.

In the main single-family district, R-1, the minimum lot is 7,000 square feet6. Buildings must sit at least 25 feet from the front lot line and 5 feet from the side lot lines7, and stand no taller than 35 feet11. Other districts have different numbers, so find the parcel's district on the zoning map before you rely on these.

We could not confirm Evansville's rules for RVs, tiny homes, accessory dwellings or minimum house size. Ask the Town of Evansville office before you plan around any of them12.

Do you need a building permit in Evansville, and who issues it?

Yes. The Town of Evansville requires a permit before anyone erects, constructs, enlarges, alters, repairs, moves or converts a building or structure inside town limits2. Permits are reviewed against the town's zoning title and the international building code and international residential code5.

The one stated exception is small: an accessory building under 120 square feet with no permanent foundation, not fixed to the ground and not attached to a permitted-use building needs no building permit, though it must still meet setbacks2.

The town's building department issues the permit after the council approves it, and a zoning certificate must come first13. A new building cannot be occupied until the building department issues a certificate of occupancy9. Town office hours are Monday to Friday, 8:00 am to 5:00 pm12.

How do septic permits work in Evansville?

The Casper-Natrona County Health Department permits the installation, repair and use of septic systems in all areas of Natrona County3. The department must be notified at least 24 hours before a system is covered, and it inspects before the system is covered with earth or used14.

We could not confirm whether a lot inside Evansville must connect to town sewer, or when a septic system is allowed there. Ask the Town of Evansville office about sewer service and the Environmental Health Division about a septic permit for the specific address1215.

The county's soils give a hint of what to expect. About 31% of soils in Natrona County rate as not limited for a conventional drain field, so many lots need a site evaluation or an engineered system16.

Building a home in Evansville: the steps, in order

  1. Find the parcel's zoning district on the zoning map at town hall, then check lot size, setbacks and height for that district10.
  2. Get a zoning certificate from the town; it comes before any building, electrical or plumbing permit13.
  3. Submit the building permit application with the approved zoning certificate, legal description, plot plan and dimensions of existing and proposed structures2.
  4. Confirm sewer service or, if septic is allowed, apply to the Casper-Natrona County Health Department3.
  5. If you plan a well, the state requires an approved permit before drilling begins8.
  6. Build with the permit in hand, then request the certificate of occupancy before moving in9.

What stays with Natrona County, and what to check before you buy in Evansville

Natrona County's zoning resolution applies to unincorporated land only, so its lot sizes, setbacks and RV rules do not govern a lot inside Evansville4. For land outside town limits, see the Natrona County page.

Septic permits for every address in Natrona County, town or not, come from the Casper-Natrona County Health Department3. Wyoming also requires a well permit before drilling a domestic well, with a $50 filing fee for domestic applications8.

For cost context, Natrona County's effective property tax rate is 0.6% and the median property tax bill is $1,608 a year1718. We could not confirm Evansville's permit fees, driveway or street access rules, or floodplain rules, so ask the town office.

Watch-outs

  • The town's zoning ordinance was last amended in April 2021 according to its own text, and fees are set by council resolution, so ask the Town of Evansville office for the current fee schedule19.
  • Do not use Natrona County's unincorporated-area rules for a lot inside Evansville; they apply only outside town limits4.
  • We could not confirm whether an owner can build their own home in Evansville without a contractor; Natrona County's owner-builder allowance applies only to unincorporated land20.

Sources

  1. Town of Evansville Zoning Ordinance (Chapter 28), amended through April 26, 2021 (Town of Evansville), quoted and re-checked
  2. Town of Evansville Zoning Ordinance (Chapter 28), amended through April 26, 2021 (Town of Evansville), quoted and re-checked
  3. Licensing — Small Wastewater Program, quoted and re-checked
  4. Natrona County 2022 Zoning Resolution, quoted and re-checked
  5. Town of Evansville Zoning Ordinance (Chapter 28), amended through April 26, 2021 (Town of Evansville), quoted and re-checked
  6. Town of Evansville Zoning Ordinance (Chapter 28), amended through April 26, 2021 (Town of Evansville), quoted and re-checked
  7. Town of Evansville Zoning Ordinance (Chapter 28), amended through April 26, 2021 (Town of Evansville), quoted and re-checked
  8. seo.wyo.gov (Wyoming statewide rule), quoted and re-checked
  9. Town of Evansville Zoning Ordinance (Chapter 28), amended through April 26, 2021 (Town of Evansville), quoted and re-checked
  10. Town of Evansville Zoning Ordinance (Chapter 28), amended through April 26, 2021 (Town of Evansville), quoted and re-checked
  11. Town of Evansville Zoning Ordinance (Chapter 28), amended through April 26, 2021 (Town of Evansville), quoted and re-checked
  12. Town of Evansville (town hall, building department and zoning) (townofevansville.org)
  13. Town of Evansville Zoning Ordinance (Chapter 28), amended through April 26, 2021 (Town of Evansville), quoted and re-checked
  14. Natrona County Wastewater Regulations, quoted and re-checked
  15. Casper-Natrona County Health Department, Environmental Health Division (casperpublichealth.org)
  16. 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
  17. Effective property tax rate: Bolthole Index county data
  18. Median property tax bill: Bolthole Index county data
  19. Town of Evansville Zoning Ordinance (Chapter 28), amended through April 26, 2021 (Town of Evansville), quoted and re-checked
  20. Building & Inspection FAQs — owner work, quoted and re-checked

Written October 24, 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 Town of Evansville

Town of Evansville’s own rules

  • Building permitRequired

    Erecting, constructing, enlarging, altering, repairing, moving or converting a building or structure inside Evansville town limits

    • Permit is issued by the town building department after a zoning certificate; construction may proceed only after the permit is issued.
    • Accessory buildings under 120 square feet that have no permanent foundation, are not fixed to the ground and are not attached to a permitted-use building do not need a building permit, but must still meet setbacks.
    • Permit application must include an approved zoning certificate, legal description, plot plan and dimensions of existing and proposed structures.

    accessory building exemption threshold: < 120 square feet (accessory buildings with no permanent foundation, not fixed to a permanent location, and not attached to a building containing a permitted use)

    “it is unlawful for any person to erect, construct, enlarge, alter, repair, move, improve, remove or convert any building or structure or cause the same to be done, without first obtaining the required permits for each building or structure from the town.”
  • Building code adoptedAdopted (with conditions)

    Building permit review and construction inside Evansville town limits

    • The ordinance names the IBC and IRC as the codes permits are reviewed against; the specific edition adopted was not stated in the section read.
    “shall review permits to ensure that the proposed construction or use complies with the requirements of this title, and the international building code (ibc) and international residential code (irc).”
  • Certificate of occupancyRequired

    Newly constructed buildings and changes in occupancy classification inside Evansville town limits

    • Certificate must state the building and proposed use comply with the zoning title, the IBC and Casper-Natrona County health department regulations.
    • Certificates must be signed by all applicable inspectors.
    “no newly constructed building shall be used or occupied and no change in the existing occupancy classification of a building or structure or portion thereof shall be made until a certificate of occupancy has been issued by the building department”
  • Local zoningPresent (with conditions)

    Private land inside the corporate limits of Evansville town, Wyoming (not unincorporated Natrona County).

    • The town's own zoning ordinance (Chapter 28) governs land use inside town limits; the ordinance states it applies to private lands within the corporate limits of the town.
    • Date shown is the original adoption/effective date; the ordinance states it was amended in 2008, 2009, 2013, 2015, 2019 and April 26, 2021, and the amended text was not reviewed for each amendment.
    “this title shall apply to all private lands within the corporate limits of the town”
  • Zoning districtsPublished (with conditions)

    Zoning districts within Evansville town limits

    • Districts are established in the town zoning ordinance (Article 5) and the official zoning map is kept at town hall per §1-19; the map itself was not opened.
    • Residential districts in the bulk table include R-1, R-2, R-3, R-4 manufactured home and UA urban agriculture; commercial and industrial districts are listed in the table of contents.
    “zoning district r-1 minimum lot size 7,000 square feet minimum setbacks front: 25’ maximum height 35' *side: 5’ minimum lot width: sixty-five feet”
  • Minimum lot sizeSpecified

    Main single-family residential district R-1 inside Evansville town limits

    • Applies to the R-1 single family residential district only; other residential districts (R-2, R-3, R-4, UA) have separate minimums in the same table.
    • Table text was extracted from PDF with some column misalignment; the value is quoted as printed.

    minimum lot size: >= 7000 square feet (R-1 district only)

    “zoning district r-1 minimum lot size 7,000 square feet minimum setbacks front: 25’ maximum height 35' *side: 5’ minimum lot width: sixty-five feet”
  • SetbacksSpecified

    Main single-family residential district R-1 inside Evansville town limits

    • Front setback 25 feet and side setback 5 feet are read from the R-1 row of the bulk table.
    • Rear setback for R-1 is not confirmed: the extracted table places a 20-foot rear value in a column layout that also includes R-2; not quoted here.
    • Table footnote text indicates a minimum of 10 feet between buildings on the same or adjacent lots.
    • Corner lots have separate setbacks in §5.3(f); not read.

    front setback: >= 25 feet (R-1 district only) · side setback: >= 5 feet (R-1 district only)

    “zoning district r-1 minimum lot size 7,000 square feet minimum setbacks front: 25’ maximum height 35' *side: 5’ minimum lot width: sixty-five feet”
  • Building heightSpecified

    Main single-family residential district R-1 inside Evansville town limits

    • Maximum height 35 feet is stated for R-1 in the bulk table; other districts differ.

    maximum building height: <= 35 feet (R-1 district only)

    “zoning district r-1 minimum lot size 7,000 square feet minimum setbacks front: 25’ maximum height 35' *side: 5’ minimum lot width: sixty-five feet”
  • Subdividing landRegulated (with conditions)

    Division of land inside Evansville town limits

    • Subdivision rules apply within the town's jurisdictional area; the ordinance refers to the town subdivision regulations for new lots, which were not read.
    • Lots created after the zoning ordinance's effective date must meet or exceed its minimum requirements and comply with the town subdivision regulations.
    “these regulations apply to all subdivision of land within the jurisdictional area of the governing body of the town of evansville”
  • Permit feesVariable (with conditions)

    Conditional use permits, variances and zone-change or amendment applications inside Evansville town limits

    • Fees are set by council resolution and maintained by the town clerk; the schedule itself was not located or read.
    • Building and zoning certificate fees are not confirmed by this source.
    “the fees for conditional use permits, variances and amendments, including zone changes, are set by the council, by resolution, as amended from time to time.”
  • Permit processPublished (with conditions)

    Zoning certificate and building permit process for construction inside Evansville town limits

    • Zoning certificate must be issued before a building, electrical or plumbing permit; certificates are valid one year.
    • Building permits are reviewed by the building department and issued after council approval per §3-2.
    • Town office: P.O. Box 158, 235 Curtis St., Evansville, WY; Mon-Fri 8:00 am - 5:00 pm.
    “after review and upon approval by the council, the building department shall issue the building permit.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Town of Evansville or Natrona County directly.

  • Owner-builder exemption — Owner-builder permit exemption inside Evansville town limits
  • Inspections — Building inspections for construction inside Evansville town limits
  • Minimum dwelling size — Minimum dwelling size inside Evansville town limits
  • Lot coverage — Maximum lot coverage inside Evansville town limits
  • Living in an RV — Living in an RV on private land inside Evansville town limits
14 more unanswered
  • Camping on your land
  • Tiny homes
  • Manufactured homes
  • Accessory dwellings
  • Who permits septic
  • Septic permit
  • Septic inspection
  • Off-grid sanitation
  • Well permit
  • Mandatory utility hookup
  • Agricultural exemption
  • Driveway access
  • Building in a floodplain
  • 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 Town of Evansville publishes no rule on the point, not that none exists. Natrona County’s page lists the county offices to call.

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