Unincorporated Washington County, Colorado requires building permits for homes and many accessory structures, but the county has not adopted a building-code ordinance12. The Land Use Office administers building and land-use permits, while the Northeast Colorado Health Department administers septic permits34.
At a glance
- Building permit
- Required for residences and many accessory structures in unincorporated areas1
- Building code
- No county building-code ordinance; applicants remain responsible for applicable codes and state standards2
- Zoning
- Administered by the Land Use Office in unincorporated Washington County3
- Septic permits
- Required before installing, altering, expanding or repairing a system through the Northeast Colorado Health Department54
- Manufactured homes
- Allowed where zoning permits, with county permitting and installation approval before occupancy6
- Tiny homes
- State approval and compliance with local zoning are required for long-term residential use7
- Owner-builder
- No permit exemption was confirmed; ask the Land Use Office8
- Private wells
- A Colorado well permit is generally required for a new groundwater well9
Who to call
Building permits
Washington County Land Use Office (Planning and Zoning)
Building permits, zoning, land-use applications and subdivision exemptions for unincorporated Washington County
Second Floor Courthouse 150 Ash Avenue Akron, CO 80720
Septic permits
Northeast Colorado Health Department OWTS Program
OWTS and septic permits for new systems and repairs in the district
700 Columbine Street Sterling, Colorado 80751
Contact details are copied from each office’s official page and were checked against it on September 29, 2026.
Do you need a building permit in Washington County, Colorado?
Yes. Unincorporated Washington County requires building permits for residences, including mobile and manufactured homes, as well as outbuildings, grain bins, garages, additions, roofed decks and screened porches1. Washington County has not adopted a county building-code ordinance, but applicants remain responsible for following Uniform Building Codes and current state standards2. The published general building-permit fee is $100, with a 1.5% use tax; a $150 Use by Special Review fee is also listed, although current charges should be confirmed because manufactured-home figures differ between forms10. No owner-builder permit exemption was confirmed, so ask the Land Use Office what documentation applies8.
Who issues building permits in Washington County, Colorado?
The Washington County Land Use Office administers permits for buildings, structures and land-use changes in the unincorporated county11. The office is on the second floor of the courthouse at 150 Ash Avenue in Akron and can be reached at (970)345-2701 ext 23411. Applications ask for property, access, proposed use, acreage, water and sewer information, while land-use applications proceed through the Planning Commission before the Board of County Commissioners12. Washington County publishes separate applications for general construction and mobile or manufactured homes, and a foundation permit may also be required for the latter1. Incorporated towns may administer their own requirements because the county office's stated jurisdiction is unincorporated Washington County3.
Does Washington County, Colorado have zoning?
Yes. Washington County's Land Use Office regulates buildings, structures and land-use changes in the unincorporated county3. Some approvals require Planning Commission and Board of County Commissioners review3. Multiple residences on less than 35 acres require Use by Special Review and health-department septic approval, while the county lists an exemption-from-subdivision route for a single residence13. General numeric rules for minimum dwelling size, minimum lot size, setbacks, lot coverage and building height could not be confirmed, so ask the Land Use Office for parcel-specific standards before relying on a site plan. The 35-acre subdivision threshold is not a general minimum lot size13.
How do septic permits work in Washington County, Colorado?
The Northeast Colorado Health Department administers onsite wastewater systems in Washington County4. Obtain its permit before installing, altering, expanding or repairing an onsite wastewater treatment system5. The application requires a site evaluation and plot plan; a separate county form also calls for a percolation test and soil-profile test pits and lists a $500 fee for either a new system or a repair514. An OWTS permit generally cannot be issued where public sewer service is available through a municipality or special district unless sewer service is infeasible or otherwise authorized5. Colorado requires final inspection before use15. About 62.1% of county soils are rated without severe limitations for a conventional drain field, but parcel testing still controls the design1614. Call the OWTS Program at (970) 867-4918 ext. 226217.
Can you live in an RV or tiny home in Washington County?
Washington County's rule for residential RV occupancy on private land could not be confirmed; ask the Land Use Office about the parcel and intended duration. The county page mentions a temporary moratorium on RV parks, but that does not answer whether one household may occupy an RV on private land. Colorado-approved tiny homes may be used for long-term living when the Division of Housing approves the plans, applicable standards are met and local zoning allows the unit7. Mobile and manufactured homes are allowed where local zoning permits them, but unincorporated Washington County requires a building permit, applicable installation inspection and an installation insignia before occupancy618. Permanent utilities cannot be released before that insignia is attached19.
Building a home in Washington County: what are the steps?
- Secure water documentation; Colorado generally requires a permit for a new groundwater well, and the county may require evidence of a water source or started application920.
- Obtain the required septic permit and complete the site and soil work14.
- For direct state-highway access, obtain a Colorado Department of Transportation permit before construction21.
What should you check before buying land in Washington County?
Confirm legal access, zoning and proposed use first; the county's exact local driveway-permit rule could not be confirmed, so ask the Land Use Office before altering an entrance. Every new Colorado groundwater well generally needs a state permit, subject to statutory and basin-specific exceptions9. Washington County receives about 16.2 inches of precipitation annually, and severe drought occurs in roughly 19.5% of years, making legal water central to due diligence2223. About 93.9% of the land has slopes of 15% or less, while wooded cover is 0%, so wind exposure may matter on buildable-looking ground2425. The effective property-tax rate is about 0.4%, with a median annual bill near $8902627. Check mapped flood risk because applicable local rules must meet or exceed federal minimum criteria28.
Watch-outs
- A Washington County building permit does not mean the county has adopted a building-code ordinance; applicants remain responsible for applicable codes and current state standards2.
- No owner-builder permit exemption was confirmed; ask the Land Use Office what documentation applies before starting work8.
- Manufactured-home occupancy requires the installation insignia, and permanent utilities cannot be released before it is attached2919.
Sources
- Planning and Zoning | Washington County, quoted and re-checked
- Building Permit Application, quoted and re-checked
- Planning and Zoning | Washington County, quoted and re-checked
- Office Locations – Northeast Colorado Health Department, quoted and re-checked
- OWTS Permit Requirements, quoted and re-checked
- Planning and Zoning | Washington County, quoted and re-checked
- Consumers of Manufactured Homes and Tiny Homes - HUD (Colorado statewide rule), quoted and re-checked
- (2026 county census)
- Water Administration (Colorado statewide rule), quoted and re-checked
- Building Permit Application, quoted and re-checked
- Washington County Land Use Office (Planning and Zoning) (washingtoncounty.colorado.gov)
- Planning and Zoning | Washington County, quoted and re-checked
- Planning and Zoning | Washington County, quoted and re-checked
- OWTS Permit Requirements, quoted and re-checked
- Title 25 - Public Health and Environment - Colorado Revised Statutes 2024 (Colorado statewide rule), quoted and re-checked
- Share of soils without severe limits for a conventional septic drain field (USDA SSURGO): Bolthole Index county data
- Northeast Colorado Health Department OWTS Program (nchd.org)
- Mobile or Manufactured Home Permit Application, quoted and re-checked
- Mobile or Manufactured Home Permit Application, quoted and re-checked
- Mobile or Manufactured Home Permit Application, quoted and re-checked
- Access Permits | Frequently Asked Questions (Colorado statewide rule), quoted and re-checked
- Annual precipitation: Bolthole Index county data
- Share of years in severe drought: Bolthole Index county data
- Share of land at 15% slope or less: Bolthole Index county data
- Wooded share of land: Bolthole Index county data
- Effective property tax rate: Bolthole Index county data
- Median property tax bill: Bolthole Index county data
- SB24-179 Floodplain Management Program (Colorado statewide rule), quoted and re-checked
- Mobile or Manufactured Home Permit Application, quoted and re-checked
Written September 29, 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.