US Land Life

Colorado

Buying Land in Adams County, Colorado

Adams County is Denver International Airport and a wide slice of the northern metro -- Thornton, Westminster, Commerce City, Brighton -- which doesn't leave much of a traditional raw-land market. What does exist is real: agricultural acreage on the eastern plains, governed by the county's own zoning code and, for parcels near the airport, a noise and land-use overlay that doesn't show up on a typical listing.

Rural Land Market: Real but Concentrated in the East

Case-by-case / verify locally

Adams County is the fifth-most-populous county in Colorado (roughly 543,000-555,000 residents) and covers about 1,166 square miles, but most of that population and built land sits inside its cities -- Thornton, Westminster, Commerce City, Brighton, Federal Heights, Northglenn, and parts of Aurora and Arvada. The county's genuine agricultural and rural-residential land is concentrated in the eastern unincorporated county, around Bennett, Strasburg, Watkins, and Henderson -- treat a land search here as targeting that specific area, not the county as a whole.

Unincorporated Zoning: A-3 Agricultural District

Generally favorable

Unincorporated Adams County is governed by the county's own Development Standards & Regulations, administered by the Community and Economic Development Department (CEDD) Planning & Development Division. The Agricultural-3 (A-3) district is written for holdings of at least 35 acres for dryland or irrigated farming, ranching, and related uses -- confirm a parcel's actual zone before assuming A-3 applies, since smaller residential-agricultural districts also exist.

DIA Airport Influence Zone / Noise Overlay

Case-by-case / verify locally

Denver International Airport sits mostly within Adams County, and the county maintains an Airport Influence Zone (AIZ) and an Airport Noise Overlay (Chapter 3-39 of county code, adopted 1983) covering areas exposed to aircraft noise. The overlay generally restricts new residential construction -- existing homes can stay and lots platted before the overlay was adopted may still build -- and requires interior noise-reduction measures where residential use is allowed. This applies to specific mapped areas near and around DIA, not the whole county, but it's a real constraint that a generic land listing won't flag.

Septic (OWTS) Through the County's Own Health Department

Could not confirm

Adams County left the multi-county Tri-County Health Department at the end of 2022 and stood up its own Adams County Health Department in January 2023, which now runs septic (OWTS) permitting locally. The county also runs a countywide septic-management program for subdivisions served by onsite systems. Confirm current septic feasibility and any management-program requirements directly with the county rather than an older source that may still reference Tri-County.

A metro county's rural land market: the eastern plains, not the whole county

Adams County stretches from the northern edge of downtown Denver out to the Kansas-facing plains, but the land buyers actually search for -- open acreage with agricultural or rural-residential character -- sits almost entirely in the county's eastern unincorporated reaches. The Town of Bennett and the unincorporated communities of Strasburg, Watkins, and Henderson anchor this area, where cattle and poultry operations and cropland persist despite the proximity of Denver International Airport and the built-up northern suburbs. Farms and ranches here trade as a real, if modest, category -- recent market figures put roughly 100,000 acres of farm and ranch land for sale countywide, concentrated in this eastern band rather than spread evenly across the county's 1,166 square miles.

That contrast matters for how you search: most of Adams County's private land and population are inside incorporated cities -- Thornton (the county's largest city, over 146,000 residents), Westminster, Commerce City, Brighton, Federal Heights, Northglenn, and portions of Aurora and Arvada -- each with its own separate zoning code, not the county's. If a listing describes itself as "Adams County land" without naming a specific unincorporated area near Bennett, Strasburg, or Watkins, confirm it's actually outside city limits and under county jurisdiction before assuming county agricultural zoning and rules apply.

Unincorporated zoning and the Denver International Airport overlay

Land use in unincorporated Adams County runs through the county's own Development Standards & Regulations, with the Community and Economic Development Department's Planning & Development Division as the point of contact (a "Planner of the Day" line is available for zoning questions). The Agricultural-3 (A-3) district -- written for parcels of at least 35 acres used for dryland or irrigated farming, ranching, or similar production -- is the relevant category for larger eastern-county holdings; the county also has other agricultural and rural-residential districts at smaller minimum sizes, so don't assume A-3's 35-acre threshold applies without confirming the specific zone on a parcel.

Adams County contains most of Denver International Airport, and the county has maintained an Airport Influence Zone (AIZ) and a formally adopted Airport Noise Overlay (county code Chapter 3-39, dating to 1983) since well before DIA opened in its current form. The overlay is meant to keep new residential and other noise-sensitive development out of areas subject to aircraft noise; new homes are generally restricted except on lots platted before the overlay's adoption, and any residential use that is allowed must meet an interior noise-reduction standard, on top of separate FAA height limits under 14 CFR Part 77 for any development near the airport. This applies to specific mapped areas around DIA, not the whole county -- but if you're evaluating a parcel anywhere in the eastern half of Adams County, ask the Planning & Development Division directly whether it falls inside the AIZ or noise overlay before assuming ordinary residential use is available.

Septic runs through the county's own health department now, not Tri-County

For years, Adams County's environmental health function -- including septic (onsite wastewater treatment system, or OWTS) permitting -- ran through the multi-county Tri-County Health Department, shared with Arapahoe and Douglas counties. That changed: Adams County's Board of Commissioners voted in October 2021 to withdraw, Tri-County Health Department formally dissolved on December 31, 2022, and the new Adams County Health Department opened its own doors in January 2023. Septic permitting is now a directly county-run function, with its own current application forms, fees, and a transfer-of-title inspection requirement.

If you're researching septic feasibility for a specific parcel and find older material referencing Tri-County Health Department, treat it as outdated -- confirm current OWTS permitting requirements directly with the Adams County Health Department.

Who to Call Before Buying Land in Adams County

Well permitting for any parcel here is a state function through the Colorado Division of Water Resources -- see the state hub, and confirm the specific well permit class DWR would issue given the parcel's size and platting history before assuming a 35-acre A-3 parcel automatically qualifies for a full exempt well.

Planning & Zoning

Adams County Community and Economic Development Department (CEDD) -- Planning & Development Division

Confirming a parcel's zoning district under the county's Development Standards & Regulations, permitted uses, the 35-acre A-3 agricultural threshold, and whether a parcel falls within the DIA Airport Influence Zone or Airport Noise Overlay.

Phone: (720) 523-6800Email: cedd-plan@adamscountyco.govOfficial website →

Environmental Health

Adams County Health Department -- Environmental Health

Septic (OWTS) permit applications, the countywide septic management program, and general environmental-health questions for unincorporated parcels.

Phone: (303) 288-6816Email: EHWaterProgram@adamscountyco.govOfficial website →

GIS / Parcel Records

Adams County Mapping / GIS

Pulling a specific parcel's zoning district, airport-overlay status, and boundaries before relying on a listing description.

Phone: (720) 523-2120Official website →

Assessor / Property Tax

Adams County Assessor

Current assessed value and property tax questions for a specific parcel.

Phone: (720) 523-6038Official website →

Recorder / Clerk / Land Records

Adams County Clerk and Recorder

Recorded deed, easement, and plat history for a specific parcel.

Phone: (720) 523-6020Official website →

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Topics Specific to Adams County

Adams County septic (OWTS) permits: process & fees →Subdividing land in Adams County: the exemption process →

Sources

  1. Planning & Development — Adams County, Colorado Government (accessed 2026-09)
  2. Chapter 3 -- Zone District Regulations, Agricultural-3 District (A-3) — Adams County, Colorado Government (hosted via Hayden Outdoors) (accessed 2026-09)
  3. Airport Influence Zone (AIZ) — Adams County, Colorado Government (accessed 2026-09)
  4. History & Profile — Adams County, Colorado Government (accessed 2026-09)
  5. Septic Systems — Adams County Health Department (accessed 2026-09)
  6. Adams County will leave the Tri-County Health Department, leaving Arapahoe County as its sole member — Colorado Public Radio (accessed 2026-09)
  7. Tri-County Health nears its end: Adams, Arapahoe to form their own health departments — FOX31 Denver / KDVR (accessed 2026-09)
  8. U.S. Census Bureau QuickFacts: Adams County, Colorado — U.S. Census Bureau (accessed 2026-09)

Last reviewed 2026-09