Bolthole Index

Arapahoe County, Colorado

Building permits, zoning and land rules in Arapahoe County, Colorado

55Index Score / 100
#30 of 64 in Colorado

Unincorporated Arapahoe County, Colorado requires a building permit for projects covered by its adopted building codes1. County zoning and subdivision rules also apply there23. Arapahoe County Public Health handles septic permits throughout the county4.

At a glance

Building permit
Required for covered projects in unincorporated Arapahoe County1
Zoning
County zoning and subdivision rules apply in unincorporated areas23
Septic permit
Required, through Arapahoe County Public Health45
Septic and lot size
No Public Health minimum; zoning guidance recommends one acre on central water or 2.5 acres on a well6
Accessory dwelling units
Allowed with a single-family detached home in listed unincorporated zoning districts7
Manufactured / tiny homes
State certification and local zoning approval required89
Owner-builder
Allowed conditionally with a signed homeowner-generated permit certificate10

Who to call

Building permits

Arapahoe County Building Division

Building permits, plan review and inspections for unincorporated Arapahoe County only

720-874-6600

Lima Plaza, 6924 S. Lima St., Centennial, CO 80112

Zoning

Arapahoe County Zoning Division

Zoning compliance, the Land Development Code, zoning violations and zoning maps for unincorporated Arapahoe County

720-874-6711

zoning@arapahoegov.com

Lima Plaza, 6924 S. Lima St., Centennial, CO 80112

Health department

Arapahoe County Public Health – Environmental Health

Septic (OWTS) construction and use permits for unincorporated Arapahoe County, under the county's OWTS regulations effective May 7, 2026

303-795-4584

6964 S. Lima St., Centennial, CO 80112

Also useful

Arapahoe County Public Works and Development

Parent department over Engineering Services, Road and Bridge, Planning and Land Development, and the Building and Zoning Divisions; the department to ask about floodplain maps or county road/driveway access

720-874-6500

6924 S. Lima St., Centennial, CO 80112

Contact details are copied from each office’s official page and were checked against it on October 16, 2026.

Off-grid gear

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

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Do you need a building permit in Arapahoe County, Colorado?

Unincorporated Arapahoe County, Colorado requires a building permit for projects covered by its adopted building codes and amendments111. Arapahoe County uses the 2021 International Residential Code and International Building Code, adopted in 2022, and the 2023 National Electrical Code, adopted in 202412. County building services stop at incorporated municipal boundaries13. Homeowners doing residential work directly must submit a signed Certificate for Home Owner-Generated Permits; the procedure does not waive building permits or inspections14. Certain three-sided agricultural shelters may qualify for a conditional waiver, but cannot have utility connections or human habitation and must satisfy zoning and floodplain rules15.

Who issues Arapahoe County building permits, and how do you apply?

The Arapahoe County Building Division, at 720-874-6600, handles building-code services for unincorporated Arapahoe County16. Create a Customer Access account to submit building applications, upload documents, communicate with case reviewers, schedule inspections and pay fees17. Residential submissions may need plans, a site plan, construction documents, professional stamps and sewer-availability documentation, depending on the project18. Building-permit fees follow a schedule the county commissioners raised effective January 1, 2021, and all fees are nonrefundable; online payments carry a $1.80 ACH transaction fee or a 3.20% credit-card transaction fee19. The Zoning Division answers parcel questions at 720-874-6711 or zoning@arapahoegov.com20. Public Works and Development, at 720-874-6500, is the starting point for Engineering Services and county road-access questions21.

Does Arapahoe County have zoning?

Arapahoe County zoning and subdivision regulations apply to unincorporated land23. Aurora sets zoning inside its city limits, and Bennett, mainly in Adams County but reaching into Arapahoe County, sets zoning inside its town limits2223. Septic permitting for parcels in Arapahoe County remains with Arapahoe County Public Health24. On unincorporated parcels, minimum lot area, setbacks, lot coverage and building height depend on district, parcel size, use and exceptions25262728. The zoning FAQ caps most nonagricultural accessory structures at 15 feet29; detached ADUs follow separate height rules, covered below. Older zoning districts and approved PUD plans can govern development; ask the Zoning Division which standards apply before designing a house303120. Subdivision exemptions still require zoning, water, sanitation, access and parcel-history compliance32. We could not confirm a countywide minimum size for a principal dwelling; ask the Zoning Division20.

How do septic (OWTS) permits work in Arapahoe County?

Arapahoe County Public Health handles septic installation, expansion, repair and use permits throughout Arapahoe County2433. A use permit is required for a sale or ownership change, a use change, a bedroom addition or a separate modular-home addition, with inspection by a certified NAWT inspector34. Public Health has no septic minimum lot size; local planning agencies typically recommend one acre with central water and 2.5 acres with a well, rather than establishing a universal septic acreage requirement6. Only 38.7% of county soils lack severe limits for a conventional drain field, so establish septic feasibility before choosing a house location35. Connecting new plumbing or buildings to an existing septic system requires advance notice to Public Health, county approval, inspection, applicable fees and an amended record drawing before final approval36. Minor pipe or chamber repairs may avoid a repair permit, but still require a licensed contractor and inspection before covering37.

Can you live in an RV or tiny home on your land in Arapahoe County?

We could not confirm a county rule allowing an RV dwelling or temporary private-land camping in unincorporated Arapahoe County; ask the Zoning Division before occupying an RV20. Colorado-approved tiny homes may be used for long-term living, subject to state approval and local zoning; we could not confirm which unincorporated districts allow a principal tiny home920. Arapahoe County allows ADUs with single-family detached homes in listed unincorporated districts, subject to a building permit, owner occupancy, deed restriction and parking rules7. Detached ADUs must be at least 400 square feet, meet district building-coverage limits and generally stay within 22 feet in height, with acreage and nonconforming-structure exceptions3839. Campers, RVs and temporary structures cannot serve as ADUs7. Certified manufactured homes require state-compliant installation where local zoning allows8.

Building a home in Arapahoe County: the steps, in order

  1. Confirm the parcel is in unincorporated Arapahoe County, because the Building Division serves only that area16.
  2. Ask the Zoning Division to confirm the district, governing code version, allowed use, dimensional standards and any subdivision review203032.
  3. If public sewer is unavailable, obtain the septic permit through Arapahoe County Public Health4037.
  4. Obtain the county right-of-way permit for new or modified access to a county road, or a CDOT permit for direct access to a state highway4142.
  5. If the site is in a floodplain or special flood-hazard area, obtain the Floodplain Development Permit before work begins43.
  6. Submit the building application and documents through Customer Access and pay the published building-permit fees1844.
  7. Schedule required building inspections through Customer Access, including sheathing/shear-wall inspection before concealment4546. Before a required certificate of occupancy can issue, complete final inspections, pay applicable fees and obtain Zoning Division and Flood Plain Administrator approval; an order suspending issuance must also be resolved4748.

What to check before you buy land in Arapahoe County

Before buying land in Arapahoe County, account for the septic use permit and certified inspection required when an existing system transfers with the property34. Septic tanks require inspection every 4 years and pumping when scum and sludge exceed 25% of effective tank volume49. New groundwater wells require a permit from Colorado Division of Water Resources, subject to statutory exemptions and basin-specific rules50. Unincorporated floodplain development needs a Floodplain Development Permit before work begins; no-impact work requires engineer certification, while impacts to a FEMA-regulated floodplain require FEMA approval of a Conditional Letter of Map Revision before county permit approval51. New or modified access to county roads, public rights-of-way or utility easements requires a Street Cut ROW Use Pothole Permit52. Short-term rentals in unincorporated Arapahoe County require county licensing and compliance with primary-residence, separation, occupancy and safety rules53.

Watch-outs

  • An Arapahoe County street address does not prove county jurisdiction; the Building Division serves unincorporated areas only16.
  • Owner-builders still need building permits and must submit a signed Certificate for Home Owner-Generated Permits54.
  • Every activity in a mapped floodplain or special flood-hazard area needs county floodplain permitting, including work expected to have no impact55.

Sources

  1. Building, quoted and re-checked
  2. Building, quoted and re-checked
  3. Codes, Criteria And Ordinances, quoted and re-checked
  4. Septic Systems, quoted and re-checked
  5. Septic Systems, quoted and re-checked
  6. Arapahoe County Public Health – Environmental Health (arapahoeco.gov)
  7. Accessory Dwelling Unit Permit Application, quoted and re-checked
  8. Consumers of Manufactured Homes and Tiny Homes - HUD (Colorado statewide rule), quoted and re-checked
  9. Consumers of Manufactured Homes and Tiny Homes - HUD (Colorado statewide rule), quoted and re-checked
  10. Residential Permitting Requirements, quoted and re-checked
  11. Building, quoted and re-checked
  12. Code Central, quoted and re-checked
  13. Building, quoted and re-checked
  14. Residential Permitting Requirements, quoted and re-checked
  15. Agricultural Exemption Application Checklist and Affidavit, quoted and re-checked
  16. Arapahoe County Building Division (arapahoeco.gov)
  17. Building, quoted and re-checked
  18. Building, quoted and re-checked
  19. Building, quoted and re-checked
  20. Arapahoe County Zoning Division (arapahoeco.gov)
  21. Arapahoe County Public Works and Development (arapahoeco.gov)
  22. Aurora: 2.1 Districts Established (Arapahoe County), quoted and re-checked
  23. Town of Bennett: Sec. 16-2-470. Land uses (Arapahoe County), quoted and re-checked
  24. Septic Systems, quoted and re-checked
  25. Arapahoe County Land Development Code, quoted and re-checked
  26. Arapahoe County Land Development Code, quoted and re-checked
  27. Arapahoe County Land Development Code, quoted and re-checked
  28. Arapahoe County Land Development Code, quoted and re-checked
  29. Zoning FAQs, quoted and re-checked
  30. Land Development Code, quoted and re-checked
  31. Land Development Code, quoted and re-checked
  32. Arapahoe County Land Development Code, quoted and re-checked
  33. Septic Systems, quoted and re-checked
  34. Septic Systems, quoted and re-checked
  35. 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
  36. Septic Systems, quoted and re-checked
  37. Septic Systems, quoted and re-checked
  38. Arapahoe County Land Development Code, quoted and re-checked
  39. Arapahoe County Land Development Code, quoted and re-checked
  40. Septic Systems, quoted and re-checked
  41. Permitting and Inspections, quoted and re-checked
  42. Access Permits | Frequently Asked Questions (Colorado statewide rule), quoted and re-checked
  43. Floodplain Permitting and Documents, quoted and re-checked
  44. Building, quoted and re-checked
  45. Building, quoted and re-checked
  46. Resolution Adopting and Amending 2021 I-Codes, quoted and re-checked
  47. Arapahoe County Building Code Resolution, quoted and re-checked
  48. Arapahoe County Building Code Resolution, quoted and re-checked
  49. Septic Systems, quoted and re-checked
  50. Water Administration (Colorado statewide rule), quoted and re-checked
  51. Floodplain Permitting and Documents, quoted and re-checked
  52. Permitting and Inspections, quoted and re-checked
  53. Arapahoe County Approves Short-Term Rental Regulations, quoted and re-checked
  54. Residential Permitting Requirements, quoted and re-checked
  55. Floodplain Permitting and Documents, quoted and re-checked

Written October 16, 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.

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Compared with neighboring counties

Like all 6 of its neighbors, Arapahoe County requires a building permit for a home.

RuleArapahoe CountyAdams CountyElbert CountyDenver CountyDouglas CountyMorgan CountyBroomfield County
Building permitRequiredRequiredRequiredRequiredRequiredRequiredRequired
County zoningYesYesYesYesYesYesYes
Septic permitsCounty Public HealthCounty Health Dept.ECPHEDenver Dept. of Public Health & Env.County Health Dept.NCHDBroomfield Health Protection Div.

County locator

Arapahoe County in Colorado

55
County map
Arapahoe County highlighted among the Colorado counties · colored by Index score

How Arapahoe County scores

Seclusion34100% ev.
Self-Sufficiency39100% ev.
Admin Boringness4190% ev.
Durability73100% ev.
Property Autonomy75100% ev.
Carry Cost77100% ev.

Evidence strength: 98%. This reports direct-source completeness and fallback use; it is separate from the score and is not a confidence interval. How it works →

$516kTypical home
0.5%Property tax
$2,773Land / acre
16.4"Annual rain
15.5% of yrsSevere drought
9.6 / yr (+8.7)Mid-century 100°F days
23 daysMid-century dry spell
1.26" (+6.5%)Mid-century 1-day rain
1.3×Wildfire change factor
100%Forward climate coverage
$2,966Home insurance / yr
4.6% / yrInsurance growth
1.2%Nonrenewal rate
county median (2+ published ZIPs)Insurance basis
4,578,168People within 2 hr
15,350Radius comparison (15 mi)
822.3People / sq mi
1.7%Federal land
94.9%Land at 15% slope or less
38.7%Soils rated "not limited" for septic (strict USDA rating)
170,863 acWorkable land screen
12.8%Wooded land
24.5 tonsBiomass / forest ac
49.5°FAvg temp

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Cities and towns in Arapahoe County

Inside a city or town, that city usually issues building permits and sets zoning; the county’s rules above cover unincorporated land. Septic, wells and floodplain rules usually stay with the county or state everywhere.

Not yet researched: Town of Deer Trail · Town of Foxfield · Littleton

Answers from the rulebook for Arapahoe County

What the ordinances and state agencies actually say — one answer per question, each quoted from the official source and independently re-checked.

Arapahoe County rules

  • Building permitRequired

    Building projects described in IRC R105 and IBC 105 in unincorporated Arapahoe County.

    • Projects are subject to current County-adopted ICC codes and posted amendments.
    • Agricultural exemption structures may qualify for a conditional waiver under Resolution 23-201.
    “Building projects, as described in section R105 of the IRC and 105 of the IBC, of the current County adopted ICC codes, including amendments posted on our website require a building permit.”
    2 more reviewed findings on this topic
    • Required — Building projects described in Section R105 of the IRC and Section 105 of the IBC for unincorporated Arapahoe County.
      “Building projects, as described in section R105 of the IRC and 105 of the IBC, of the current County adopted ICC codes, including amendments posted on our website require a building permit.”
    • Required — Building projects described in IRC section R105 and IBC section 105 under current county-adopted ICC codes.
      “Building projects, as described in section R105 of the IRC and 105 of the IBC, of the current County adopted ICC codes, including amendments posted on our website require a building permit.”
  • Owner-builder exemptionConditional

    Homeowner-generated residential permit work.

    • A signed Certificate for Home Owner-Generated Permits is required when work is done directly by the homeowner instead of a licensed contractor.
    • The source does not establish a complete exemption from permits or inspections.
    “If any work is done directly by the homeowner instead of a licensed contractor, please provide a signed Certificate for Home Owner-Generated Permits.”
    2 more reviewed findings on this topic
    • Conditional — Work performed directly by a homeowner instead of a licensed contractor in residential permitting.
      “If any work is done directly by the homeowner instead of a licensed contractor, please provide a signed Certificate for Home Owner-Generated Permits.”
    • Conditional — Residential work performed directly by the homeowner instead of a licensed contractor.
      “If any work is done directly by the homeowner instead of a licensed contractor, please provide a signed Certificate for Home Owner-Generated Permits.”
  • Building code adoptedAdopted

    Current county-adopted building codes for unincorporated Arapahoe County.

    • The county adopted current codes by Resolution No. 21-394 on April 1, 2022.
    • The page identifies the 2021 International Building Code and International Residential Code and states that the county adopted the 2023 National Electrical Code on July 9, 2024.

    adoption date: 2022-04-01 · NEC edition: 2023 (Adopted July 9, 2024)

    “The Arapahoe Board of County Commissioners adopted the current building codes by Resolution NO. 21-394 on April 1, 2022.”
    2 more reviewed findings on this topic
    • Adopted — County building codes governing construction and occupancy in the county building jurisdiction.
      “NOW, THEREFORE, BE IT FURTHER RESOLVED that the Board of County Commissioners of Arapahoe County hereby adopts the 2021 editions of the International Building Code, the International Residential Code, the International Plumbing Code, the International Mechanical Code, the International Fuel Gas Code, the International Existing Building Code, the International Swimming Pool and Spa Code, the 2021 edition of the International Energy Conservation Code”
    • Adopted — County building code administration in unincorporated Arapahoe County.
      “The Arapahoe Board of County Commissioners adopted the current building codes by Resolution NO. 21-394 on April 1, 2022.”
  • InspectionsRequired

    Construction or work for which a County building permit is required.

    • Required inspections include final inspections before a certificate of occupancy may issue.
    • The amended residential provisions require inspection before concealment for building sheathing/shear walls.
    “Construction or work for which a permit is required shall be subject to inspection by the building official.”
    2 more reviewed findings on this topic
    • Required — Permitted building projects for which a certificate of occupancy is required.
      “Periodic, partial inspections shall be made to determine compliance with Chapter 13 and shall include, but not be limited to, inspections for: envelope insulation R and U values, fenestration U value, duct system R value, and HVAC and water-heating equipment efficiency.”
    • Limited — Building work for new or existing structures subject to Arapahoe County Building Division services in unincorporated Arapahoe County.
      “The Building issues permits, inspects work and reviews construction plans to ensure that all building projects for new or existing structures are safe and conform to code.”
  • Certificate of occupancyRequired

    Projects requiring a certificate of occupancy under the county building code.

    • All required final inspections must be completed.
    • All applicable county and other department fees collected or enforced through the code must be paid.
    • The project must not be subject to an order or directive suspending issuance.
    • Approval by the Zoning Division and Flood Plain Administrator is required after compliance is found.
    “A certification affidavit shall be required upon completion of the permitted project and prior to the issuance of any required Certificate of Occupancy.”
  • County-wide zoningPresent (with conditions)

    Zoning under the Arapahoe County Land Development Code in unincorporated areas.

    • The official codes page describes the Land Development Code as applying to unincorporated areas of Arapahoe County.
    • Many neighborhoods are zoned under previous versions of the Land Development Code.
    “View zoning and subdivision regulations for unincorporated areas of Arapahoe County.”
    One more reviewed finding on this topic
    • Present (with conditions) — Zoning and subdivision regulation in unincorporated Arapahoe County.
      “View zoning and subdivision regulations for unincorporated areas of Arapahoe County.”
  • Local zoningPresent (with conditions)

    County zoning and use determinations for properties located within unincorporated Arapahoe County.

    • The county Building Division and zoning services apply only to unincorporated parts of Arapahoe County.
    • Use determinations evaluate the proposed use under the Land Development Code.
    • Incorporated municipalities are outside this county-service scope and may administer their own land-use rules.
    “Use Determination - A formal request to confirm permitted uses of a specific property located within unincorporated Arapahoe County.”
  • Zoning districtsPublished (with conditions)

    Zoning districts and associated development standards in the unincorporated area of Arapahoe County.

    • The current Land Development Code page states an effective date of November 9, 2021 and an update date of May 12, 2026.
    • Many neighborhoods are zoned under a previous version of the Land Development Code; the county publishes links to obsolete zoning districts.
    • The Code states that permitted uses are listed in Chapter 3 and development regulations are in Chapters 4 and 5.
    • Some listed districts may have a PUD designation, in which case development follows the approved PUD plan.
    • Obsolete-designation parcels as of April 1, 2017 may be developed under the obsolete district regulations or an existing approved PUD plan.
    “The unincorporated area of Arapahoe County is hereby divided into zoning districts as listed in Section 2-2, Table 2-2.1: Zoning District Summary Table.”
    2 more reviewed findings on this topic
    • Published (with conditions) — Zoning districts and district-specific standards in unincorporated Arapahoe County.
      “Many neighborhoods in Arapahoe County are zoned under a previous version of our Land Development Code. The links below provide information about these obsolete zoning districts:”
    • Published — Published County zoning districts and prior-version zoning districts in unincorporated Arapahoe County.
      “Many neighborhoods in Arapahoe County are zoned under a previous version of our Land Development Code. The links below provide information about these obsolete zoning districts:”
  • Minimum lot sizeSpecified

    Lots and parcels subject to the Arapahoe County Land Development Code zoning districts.

    • Minimum lot area varies by zoning district and parcel category.
    • Undersized legally created parcels may use separate performance standards and exceptions.
    • Prior Code versions may apply in some neighborhoods.
    “This Code specifies minimum lot area, width, and setback/yard requirements within each zoning district for the purpose of creating “building envelopes” in which construction can occur on any parcel in the unincorporated areas of Arapahoe County.”
  • SetbacksSpecified

    Primary and accessory structures in unincorporated County zoning districts.

    • Setbacks vary by zoning district and parcel size.
    • For certain undersized parcels, standards include front, side, rear, and side-corner setbacks from 25 to 100 feet.
    • Exceptions include clustered residential lots, legally created parcels, and pre-September 1, 2020 RR-A accessory buildings with qualifying permits or affidavits.
    “All primary and accessory structures in undersized parcels in the A-E and A-1 zone districts shall comply with the dimensional standards in Table 4-1.2, unless an exception or a different standard is stated in another section of this LDC.”
  • Lot coverageSpecified

    Residential zoning districts and clustered residential lots in unincorporated Arapahoe County.

    • Maximum lot coverage is district-specific.
    • Primary building setbacks and maximum lot coverage on clustered residential lots may not be smaller than 75 percent of those required in the zone district.

    clustered residential lot coverage floor: >= 75 percent of zone-district requirement (Applies to primary building setbacks and maximum lot coverage on clustered residential lots)

    “Primary building setbacks and maximum lot coverage on clustered residential lots may not be smaller than 75 percent of those required in the zone district.”
    One more reviewed finding on this topic
    • Specified — Applicable zoning districts and accessory dwelling units.
      “Detached ADUs shall comply with the total maximum building coverage requirements of the applicable zoning district.”
  • Building heightSpecified

    Buildings and structures governed by applicable County zoning districts.

    • Building height varies by zoning district and use.
    • Attached ADU height may not exceed the principal dwelling allowance.
    • Detached ADUs generally may not exceed 22 feet, subject to stated acreage and nonconforming-structure exceptions.

    detached ADU maximum height: <= 22 feet (Lots or parcels of 19 or more acres and legally nonconforming detached structures are excepted as stated in the Code.)

    “Except as provided for in paragraph 11.c and 11.d below, the maximum building height of a Detached ADU shall not exceed 22 feet.”
    One more reviewed finding on this topic
    • Specified — Buildings and accessory structures in applicable unincorporated Arapahoe County zoning districts.
      “Except for agricultural usage only, accessory structures shall not exceed 10% of the lot area or a maximum of 1,000 square feet, and a maximum building height of 15 feet.”
  • Accessory dwellingsLimited

    Accessory dwelling units accompanying single-family detached residences in unincorporated Arapahoe County.

    • ADUs are allowed in the listed agricultural and residential zoning districts and in R-2, R-3, R-3S, R-4, R-5, and MU; PUDs allow ADUs except where they are listed as a prohibited use.
    • The ADU must comply with the governing zoning district's dimensional standards; planned unit development standards take precedence where they conflict with Section 3-3.2.D.
    • Only one ADU is allowed per lot or parcel, and it must be on the same lot or parcel as the principal dwelling.
    • The principal single-family dwelling must be used as such; a single-family detached dwelling must exist or be constructed concurrently, and the ADU certificate of occupancy follows issuance of the principal dwelling's certificate of occupancy.
    • The ADU must be under the same ownership as the principal dwelling and may not be sold separately.
    • A building permit is required before construction or conversion; compliance is reviewed at building-permit application.
    • The property owner of record must reside in either the principal dwelling or ADU. The Planning Division Manager or designee may waive this for temporary absences of less than one year if the owner maintained the permitted use for at least two years and submits satisfactory proof.
    • Before obtaining a certificate of occupancy, the owner must record a deed restriction with the Arapahoe County Clerk and Recorder imposing the stated use, size, sale, subdivision, successor-ownership, and owner-occupancy restrictions.
    • One additional off-street parking space is required for the ADU.
    • Attached ADUs may not exceed 50 percent of the principal dwelling's size. Detached ADUs must be at least 400 square feet and generally may not exceed the smaller of 40 percent of the principal dwelling or the applicable table limit; the Code lists 600 square feet for 5,000–6,999 square-foot lots, 850 square feet for 7,000–12,499 square-foot lots, 1,000 square feet for 15,500–39,999 square-foot lots, and 1,200 square feet for 40,000 square feet to under 19 acres.
    • Detached ADUs generally must be at least 10 feet behind the principal dwelling's front building line and at least 5 feet from the principal dwelling; specified exceptions apply to legally nonconforming structures and lots or parcels of 19 or more acres.
    • Detached ADUs generally have a maximum height of 22 feet, with exceptions for lots or parcels of 19 or more acres and certain legally nonconforming structures.
    • ADUs must meet applicable building, fire, utility, water, wastewater, outdoor-area, landscaping, design, lighting, and private covenant requirements. For private wastewater systems, approval from the Arapahoe County Public Health Department is required for both the principal dwelling and ADU.
    • ADUs may not be used for short-term rental except where the underlying property is nine acres or greater. Mobile homes, campers, recreational vehicles, camper buses, shipping containers, storage containers, and other temporary structures are prohibited for use as an ADU.
    • The county webpage states that ADU applications are reviewed by Zoning and Building and may also be reviewed by Engineering Services, a local fire district, or a stormwater management authority; it gives a typical eight-to-twelve-week review timeframe for single-family building permit applications. Building permit, use tax, plan review, recording, utility, engineering, and potentially transportation or drainage fees may apply.

    maximum ADUs per lot or parcel: 1 ADU · attached ADU maximum size: <= 50 percent of principal dwelling · detached ADU minimum size: >= 400 square feet · detached ADU maximum size for 5,000–6,999 square-foot lots: 600 square feet · detached ADU maximum size for 7,000–12,499 square-foot lots: 850 square feet · detached ADU maximum size for 15,500–39,999 square-foot lots: 1000 square feet · detached ADU maximum size for 40,000 square-foot to under 19-acre lots: 1200 square feet · detached ADU minimum separation from principal dwelling: >= 5 feet (Subject to the Code's stated exceptions.) · detached ADU setback behind principal dwelling front building line: >= 10 feet (Generally applicable; exceptions apply to legally nonconforming existing accessory structures and lots or parcels of 19 or more acres.) · detached ADU maximum building height: <= 22 feet (Exceptions apply to lots or parcels of 19 or more acres and certain legally nonconforming detached structures.) · short-term rental minimum underlying property size exception: >= 9 acres (ADUs may not be used for short-term rental except where the underlying property is nine acres or greater.) · owner temporary-absence waiver: less than one year (Owner must have maintained the permitted use for a minimum of two years and submit satisfactory proof.)

    “ADUs are allowed in unincorporated Arapahoe County in conjunction with single-family detached residences in the following zoning districts: A-E R-1-A R-2 MU A-1 R-1-B R-3 PUD, except where ADUs are a prohibited use RR-A R-1-C R-3S RR-B R-1-D R-4 RR-C R-2-A R-5”
    One more reviewed finding on this topic
    • Limited — Accessory dwelling units in applicable unincorporated Arapahoe County zoning districts.
      “A Detached ADU shall not be less than 400 square feet.”
  • Who permits septicCounty

    OWTS installation, repair, and use in Arapahoe County.

    • Arapahoe County Public Health administers county OWTS permitting.
    • County OWTS regulations and Colorado OWTS regulations are both listed as applicable resources.
    “Arapahoe County Public Health permits the installation, repair, and use of these systems in the County.”
    2 more reviewed findings on this topic
    • County — Installation, repair, and use of onsite wastewater treatment systems in Arapahoe County.
      “Arapahoe County Public Health permits the installation, repair, and use of these systems in the County.”
    • County — On-site wastewater treatment systems in Arapahoe County.
      “Arapahoe County Public Health permits the installation, repair, and use of these systems in the County.”
  • Septic permitRequired

    New OWTS installations, expansions, repairs, and use.

    • A septic permit is required for new installations, expansions, repairs, and use.
    • Minor repairs such as a single pipe or chamber may not require a permit, but must be performed by a licensed contractor and inspected before being covered.
    • More extensive tank or soil-treatment-area damage may require a repair permit.
    “A septic permit is required for new installations, expansions, repairs and use.”
    2 more reviewed findings on this topic
    • Required — New onsite wastewater installations, expansions, repairs, and use permits in Arapahoe County.
      “A septic permit is required for new installations, expansions, repairs and use.”
    • Required — New OWTS installations, expansions, repairs, and use permits in Arapahoe County.
      “A septic permit is required for new installations, expansions, repairs and use.”
  • Septic inspectionRequired

    Septic tanks serving on-site wastewater treatment systems in Arapahoe County.

    • Tanks must be pumped when scum and sludge accumulate to greater than 25% of the effective volume of the tank.
    • Dosing tanks must be inspected and pumped if sludge accumulation is observed.
    • More frequent pumping may be appropriate for higher-than-average use.
    • All pumping and evaluation should be done by a licensed cleaner.

    inspection interval: 4 years · scum and sludge threshold: > 25 percent of effective tank volume (tank must be pumped)

    “We require that septic tanks be inspected every four years and pumped when scum and sludge accumulate to greater than 25% of the effective volume of the tank.”
    One more reviewed finding on this topic
    • Required — On-site wastewater treatment system use permits in Arapahoe County.
      “Use permit inspections must be conducted by a Certified NAWT Inspector.”
  • Mandatory utility hookupConditional

    Connecting new plumbing or buildings to an existing OWTS.

    • Owner must notify Arapahoe County Public Health in advance.
    • County approval is required.
    • Inspection of new plumbing and applicable fees are required.
    • The existing record drawing must be amended before final approval.
    “We generally allow connection to the existing septic system, provided the owner notifies Arapahoe County Public Health in advance, and we approve the connection. An inspection of the new plumbing and applicable fee(s) is required.”
    One more reviewed finding on this topic
    • Conditional — Connection of new plumbing in a garage, barn, or similar structure to an existing septic system.
      “We generally allow connection to the existing septic system, provided the owner notifies Arapahoe County Public Health in advance, and we approve the connection. An inspection of the new plumbing and applicable fee(s) is required. Prior to final approval, the existing record drawing of the system must also be amended to show new buildings and plumbing.”
  • Agricultural exemptionConditional

    Certain three-sided agricultural structures in A-E, A-1, or RR-A zoning districts.

    • The structure must be enclosed on no more than three sides.
    • It must shelter only agricultural implements, farm products, livestock, or poultry.
    • It must comply with zoning, setback, area, height, and floodplain rules.
    • It may not have plumbing, electrical equipment or service, other utility connections, human habitation, public access, or prohibited employment/recreational uses.
    • A later change of use requires a building permit, fees, inspections, and certificate of occupancy; separate plumbing, mechanical, or electrical permits may be required.
    “In order to qualify for an exemption from building permit under this Resolution, a proposed structure or building shall meet the following requirements:”
  • Subdividing landRegulated (with conditions)

    Subdivision and subdivision-exemption procedures in unincorporated Arapahoe County.

    • Subdivision exemptions require compliance with specified criteria, including zoning, water, sanitation, access, parcel-history, and anti-circumvention requirements.
    • An application may instead be required to proceed as a subdivision or minor subdivision if the exemption process would circumvent the regulations.
    • No more than four lots or parcels may be created from a 35-acre maximum-sized parcel under the cited criteria.

    maximum parcels under cited exemption criterion: <= 4 parcels (From a 35-acre maximum-sized parcel.)

    “No more than four lots or parcels shall be created from a 35 acre maximum sized parcel.”
    2 more reviewed findings on this topic
    • Regulated (with conditions) — Zoning and subdivision regulation in unincorporated Arapahoe County.
      “View zoning and subdivision regulations for unincorporated areas of Arapahoe County.”
    • Regulated (with conditions) — Subdivision and subdivision exemptions in unincorporated Arapahoe County.
      “View zoning and subdivision regulations for unincorporated areas of Arapahoe County.”
  • Driveway accessRequired

    Construction or modification of access points from private property to County roadways or from public rights-of-way to private property or utility easements.

    • A Street Cut ROW Use Pothole Permit is required for the stated access-point work.
    • The page also lists emergency repair timing: application within 48 hours after work begins.
    “Required for the construction or modifications of access points from private property to County roadways or Access from Public Right-of-Way to private property or utility easements.”
    One more reviewed finding on this topic
    • Required — Construction or modification of access points from private property to county roadways, public rights-of-way, or utility easements.
      “Required for the construction or modifications of access points from private property to County roadways or Access from Public Right-of-Way to private property or utility easements.”
  • Building in a floodplainRequired

    All development proposed, constructed, installed, commenced, improved, or maintained within a floodplain or special flood hazard area in unincorporated Arapahoe County.

    • A Floodplain Development Permit must be obtained from the Floodplain Administrator before construction or development begins.
    • All activities require permitting regardless of impact.
    • If the project will not cause an impact to the floodplain, a No-Impact FDP is required with an Engineer’s Certification of No-Impact.
    • If the project will cause an impact to a FEMA-regulated floodplain, a Conditional Letter of Map Revision must be submitted to and approved by FEMA before approval of the FDP.
    • The county's Land Development Code and subdivision regulations apply to unincorporated areas of Arapahoe County.
    “All activities, regardless of impact, are required to be permitted.”
    2 more reviewed findings on this topic
    • Required — All development proposed, constructed, installed, commenced, improved, or maintained within a floodplain or special flood hazard area in unincorporated Arapahoe County.
      “All activities, regardless of impact, need to be permitted.”
    • Required — All development proposed, constructed, installed, commenced, improved, or maintained within a floodplain or special flood hazard area.
      “All development proposed within floodplain or special flood hazard areas and all development constructed, installed, commenced, improved, or maintained within a floodplain or special flood hazard area is required to obtain a Floodplain Development Permit (FDP) from the Floodplain Administrator before construction or development begins within any floodplain or special flood hazard area. All activities, regardless of impact, need to be permitted.”
  • Short-term rentalsLimited

    Short-term rentals in unincorporated Arapahoe County.

    • County STR regulations require licensing and impose primary-residence, separation, occupancy, safety, and responsible-agent requirements.
    • Legacy operators may qualify for an exemption if they operated within six months before the ordinance took effect and applied within 60 days after the regulations took effect; the County states June 20, 2026 as the deadline date for legacy requests.
    • The source states an initial $200 application fee and $350 annual license fee.

    initial application fee: 200 USD · annual license fee: 350 USD · separation from existing licensed rental: >= 500 feet (Legacy-qualified properties exempt.)

    “Only a property owner or long-term lessee may apply for a STR license, and the property must serve as the applicant’s primary residence, unless it qualifies for a legacy exemption.”
  • Permit feesPublished (with conditions)

    County building permitting and online payment process.

    • Building permit fees are non-refundable.
    • The County states fees increased effective January 1, 2021.
    • Online payments have transaction fees; the page states a new ACH fee of $1.80 and credit-card fee of 3.20 percent starting September 22, 2025.

    ACH transaction fee: 1.8 USD (Starting September 22, 2025.) · credit card transaction fee: 3.2 percent (Starting September 22, 2025.)

    “Starting Sept. 22, 2025, there will be new fees. Electronic Check (ACH) with a transaction fee of $1.80 or Credit Card (Visa, Mastercard, Discover or American Express) with a transaction fee of 3.20 percent.”
    2 more reviewed findings on this topic
    • Published — County building permit and re-inspection fees for unincorporated Arapahoe County.
      “The Board of County Commissioners approved an increase in fees, effective January 1, 2021. All fees are non-refundable.”
    • Published (with conditions) — County building permits and related transactions.
      “Starting Sept. 22, 2025, there will be new fees. Electronic Check (ACH) with a transaction fee of $1.80 or Credit Card (Visa, Mastercard, Discover or American Express) with a transaction fee of 3.20 percent.”
  • Permit processPublished (with conditions)

    County building permit applications.

    • Customer Access is used to apply, upload documents, communicate with case managers, schedule inspections, and make fee payments.
    • Residential applications may require plans, site plans, construction documents, engineering or architect stamps, sewer availability documentation, and online fee payment depending on project type.
    • Plans reviewers check applications for completeness and accuracy before permit issuance.
    “Customer Access is the online full-service tool that allows you to submit applications, upload documents, communicate with case reviewers, schedule inspections and make payments.”
    2 more reviewed findings on this topic
    • Published (with conditions) — County building permit applications in unincorporated Arapahoe County.
      “Customer Access is the online full-service tool that allows you to submit applications, upload documents, communicate with case reviewers, schedule inspections and make payments.”
    • Published (with conditions) — County building-permit application and inspection scheduling process.
      “Customer Access is the online full-service tool that allows you to submit applications, upload documents, communicate with case reviewers, schedule inspections and make payments.”

Colorado rules that apply here

  • Tiny homesAllowed (with conditions)

    Colorado Division of Housing-regulated tiny homes intended for residential occupancy and long-term living.

    • Plans must be submitted to the Colorado Division of Housing for approval before construction of the units.
    • The unit must satisfy applicable Colorado-adopted codes and standards and local zoning requirements.
    • Tiny home units are certified for the specific site where installed; relocation to another Colorado site requires the applicable design criteria, and design differences require revisions.

    foundation types: permanent or temporary

    “Tiny homes are approved for long term living”
  • Manufactured homesAllowed (with conditions)

    Installation and resulting residential use of HUD-code manufactured homes and mobile homes in Colorado, subject to Colorado Division of Housing requirements and local zoning or building requirements.

    • HUD homes must be certified by the applicable State Administrative Agent for installation in Colorado; imported units are monitored by the State Administrative Agent of the state from which they are imported, rather than necessarily by Colorado's SAA.
    • A HUD home may be installed anywhere in Colorado only where local zoning allows it.
    • Local jurisdictions may require site mitigation to meet local wind and snow loads, but the mitigation cannot directly affect or change the construction of the home itself.
    • The Division of Housing regulates installation and installation inspections for HUD homes; mobile-home foundation and structural construction requirements are regulated by local jurisdictions with active building departments.
    • The state minimum HUD design criteria listed by the source are Wind Zone 1, Thermal Zone 3, and Middle Roof Load Zone (30 psf).

    wind zone: 1 zone · thermal zone: 3 zone · roof load zone: 30 psf (Middle Zone)

    “HUD homes [...] can be installed anywhere in Colorado as long as the local zoning allows for it.”
  • Off-grid sanitationLimited

    Sanitation for dwellings and occupied structures statewide that is provided without connection to a sewage treatment works.

    • The structure must have adequate facilities for sanitary disposal of sewage.
    • An OWTS may be used subject to applicable permit, inspection, construction, installation, alteration, and use requirements.
    • Construction of new cesspools is prohibited.
    • Septage removed during maintenance or cleaning must be disposed of at an approved site and in an approved manner.
    “No person shall construct or maintain any dwelling or other occupied structure that is not equipped with adequate facilities for the sanitary disposal of sewage.”
  • Well permitRequired

    Every new groundwater-diverting well in Colorado, including residential wells, subject to statutory exemptions and basin-specific rules.

    • The Division of Water Resources administers groundwater permitting and issues permits.
    • Applicants must complete the appropriate application and pay the associated fee.
    • Statutory exemptions and additional Denver Basin or Designated Basin rules may affect the requirement or permit conditions.
    • In many areas, a well may also require an augmentation plan if its priority is not sufficient to divert in priority.

    complete-application review time: <= 49 days (DWR states review of complete new and replacement applications may take up to 49 days)

    “Every new well in the state that diverts groundwater must have a well permit.”
  • Campground & park staysAllowed (with conditions)

    Temporary overnight camping, including parking a motor home or traveler, on land and water under the control of Colorado Parks and Wildlife, including state parks and state recreation areas.

    • The source addresses lands and waters under the control of the Division of Parks and Wildlife, not all public or private land statewide.
    • Camping includes parking a motor vehicle, motor home, or traveler for the apparent purpose of overnight occupancy.
    • A commission-issued permit may be required; the statute defines permits to include campground permits and electrical hookup permits.
    • The state may charge fees for required passes or permits for use of any state park or state recreation area where supervision, maintenance, or specified facilities warrant a fee.

    overnight occupancy: true (Camping definition includes the parking of a motor vehicle, motor home, or traveler for the apparent purpose of overnight occupancy.) · permit types: campground permits; electrical hookup permits

    “Develop state parks and state recreation areas suitable for such recreational activities as camping, [...] "Camping" means [...] the parking of a motor vehicle, motor home, or traveler”
  • county zoning authorityGeneral

    Colorado counties adopting zoning plans for all or any part of unincorporated territory.

    • The county planning commission may make the zoning plan; in a county having a county planning commission, it must do so upon order by the board of county commissioners.
    • The zoning plan may regulate districts or zones, including building location, height, bulk, size, lot coverage, lot size, open spaces, population density, building and land uses, and access to sunlight for solar energy devices.
    • The plan may include regulations for uses on or along storm or floodwater runoff channels or basins only when the channel or basin has been designated and approved by the Colorado water conservation board, to lessen or avoid hazards from storm or floodwaters.
    • The statute applies to unincorporated territory and does not describe incorporated cities or towns as within this county zoning grant.
    “zoning all or any part of the unincorporated territory within such county”
  • county building authorityGeneral

    Colorado counties adopting and enforcing building codes and requiring building permits in designated unincorporated areas.

    • A board of county commissioners may adopt a building code in all or part of the county, but the area must not be within the limits of an incorporated city or town.
    • Buildings or structures used solely to shelter agricultural implements, farm products, livestock, or poultry may be excepted from the building code and permit requirement.
    • Before adoption, the county planning commission may designate part or all of the county for the building code upon request from the board of county commissioners; the board must hold a public hearing and publish notice once weekly for four consecutive weeks.
    • After adoption of the building code, construction, reconstruction, alteration, or remodeling in the designated area requires a building permit, except for the agricultural-shelter exception.
    • The board must fix a reasonable schedule of building-permit fees; no permit fee may be charged unless a qualified inspector actually performs an inspection.
    • Plans must conform to the building code, and plans and specifications generally must bear the seal of a Colorado-licensed architect or engineer unless exempted by section 12-120-403.
    • Every county adopting or updating a building code must adopt and enforce an energy code meeting or exceeding one of the three most recent International Energy Conservation Code versions under section 30-28-211.
    • The 2025 amendment to section 30-28-204 is effective January 1, 2026 and adds accessibility requirements for substantially amended or updated county building codes, with an exception for compliant one- and two-family dwellings and townhomes.
    “A board of county commissioners is authorized to adopt ordinances and a building code”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission — ask the county directly.

  • Minimum dwelling size — Minimum size of principal dwellings in unincorporated Arapahoe County.
  • Living in an RV — Long-term or residential RV occupancy on private property.
  • Camping on your land — Temporary camping on private property in unincorporated Arapahoe County.

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.

Water rights & wells in Arapahoe County

Whether a new home can legally get its own water here — the sub-state groundwater regime, from Colorado’s water agency.

Over-appropriated / declining

The aquifer here is over-appropriated and declining. A domestic well is usually still permit-exempt, but long-term supply is a genuine risk.

Household wellExempt up to a limit

A household obtains water via a permit-exempt small-capacity well (15 gpm) under CRS 37-92-602 outside designated basins or CRS 37-90-105 inside them; on a 35-acre-plus lot limited outside/stock/1-acre irrigation is allowed.

Limit: Household-use-only well: 15 gpm, ≤0.33 acre-ft/yr, indoor only. Domestic well on a 35+ acre tract: 15 gpm, ≤1 acre-ft/yr.

Colorado DWR — Guideline 2023-1, Exempt & Small-Capacity Wells ↗
  • Lost Creek Designated Ground Water Basinpartial of county

    Lost Creek designated basin NE of Denver; over-appropriated alluvial aquifer, new large-capacity appropriations limited. Small-capacity/domestic wells still permitted.

    Colorado DWR — Designated Basins / Division 3 ↗
  • Kiowa-Bijou Designated Ground Water Basinpartial of county

    New wells require a Ground Water Commission permit; new large-capacity alluvial appropriations limited by prior appropriation, while Denver Basin bedrock is allocated by overlying acreage on a 100-year aquifer life.

    Colorado DWR — Designated Basins ↗
  • Denver Basin nontributary bedrock aquifers (Dawson, Denver, Arapahoe, Laramie-Fox Hills)partial of county

    Nontributary bedrock groundwater is allocated to the overlying landowner on an assumed 100-year aquifer life and needs a well permit; finite and steadily declining.

    Colorado Water Knowledge (CSU) — Groundwater Rights ↗

Prior-appropriation state (first in time, first in right). Groundwater rules change and basin boundaries follow the aquifer, not the county line — confirm current well and appropriation rules with the Colorado state water agency before you buy or drill.Groundwater governance as of Jul 2026, cited to each administering agency.

Living off-grid in Arapahoe County, Colorado

Is Arapahoe County a good place to live off-grid or homestead?

Arapahoe County scores 55/100 on the Bolthole Index, a solid county profile. Its strengths: manageable long-term carry cost and a stronger property-autonomy legal backdrop. Watch-outs: sparse surroundings — about 15,350 people within 15 miles and thin water margin (16.4″/yr rainfall).

Do you need a building permit in Arapahoe County, Colorado?

Arapahoe County generally requires a residential building permit, and it enforces county zoning. Onsite septic is permitted by Arapahoe County Public Health - Environmental Health. Owner-builders may act as their own contractor to build their home. These answers are quoted from official sources and independently re-checked. Rules change and cities within the county differ — always confirm with the county before you buy or build.

How much does land cost in Arapahoe County, Colorado?

Land in Arapahoe County runs about $2,773 per acre, based on the latest county data.

What is the water situation in Arapahoe County?

Arapahoe County gets about 16.4" of rain a year, with severe drought in roughly 15.5% of years. On water rights, Arapahoe County lies in the Lost Creek Designated Ground Water Basin — Lost Creek designated basin NE of Denver; over-appropriated alluvial aquifer, new large-capacity appropriations limited. Small-capacity/domestic wells still permitted..

How remote is Arapahoe County?

A typical private-land location has about 15,350 people within 15 miles and 4,978,888 within 100 miles. These radius catchments are the published fallback where road routing is unavailable.

How Arapahoe compares in Colorado

Compare side-by-side →See all 64 Colorado counties ranked →