Whether you need a permit before having fill dirt delivered in the Denver metro depends less on a single statewide rule and more on which city or county has jurisdiction over your address — and that jurisdiction varies more in Colorado than it does in most states, because several well-known "suburbs" (Highlands Ranch, unincorporated parts of Jefferson and Arapahoe counties) have no city government of their own. Below is what we could verify directly from city and county sources, and — just as important — which cities publish no small-residential threshold at all, so you know when to call ahead rather than assume.
Statewide Rule: The 1-Acre Stormwater Trigger
Regardless of which city or county you're in, the Colorado Discharge Permit System (CDPS) General Permit (COR400000), administered by the Colorado Department of Public Health and Environment (CDPHE), requires stormwater permit coverage for any construction activity disturbing 1 acre or more of land — including smaller sites that are part of a larger common development plan totaling an acre or more. This is separate from, and in addition to, any local grading permit. Most residential fill-dirt deliveries (yard leveling, foundation backfill, a pool fill) fall well under an acre of disturbance, but subdivision-scale grading does not.
FEMA-mapped 100-year floodplain fill also triggers a local Floodplain Development Permit statewide, enforced by whichever city or county is the floodplain administrator for that parcel. If your property borders a creek, the South Platte, or any mapped drainageway, check this before ordering fill regardless of volume.
Boulder (City)
The City of Boulder requires a grading permit for any cut or fill exceeding 50 cubic yards, with no published small-residential exemption below that. Boulder also requires a Floodplain Development Permit for any fill placement inside the FEMA floodplain, independent of volume. Contact Boulder's Planning & Development Services before ordering material near that threshold.
Boulder County (Unincorporated)
Outside Boulder's city limits — including many outlying properties near Longmont, Lyons, and Niwot — Boulder County uses a tiered system: 50 cubic yards or less requires no review; between 50 and 500 cubic yards requires an Expedited Site Plan Review plus a Grading Permit; 500 cubic yards or more requires a Limited Impact Special Use Review plus a Grading Permit. These thresholds are cumulative per parcel, not per delivery. Boulder County Community Planning & Permitting: (303) 441-3930.
Jefferson County (Unincorporated)
For unincorporated Jefferson County properties (relevant if your address is near, but not inside, Lakewood, Arvada, or Golden city limits), a grading permit is required once disturbance exceeds 0.5 acre (21,780 sq ft), and stockpiling 5,000 cubic yards or more of unused material also triggers a permit on its own. Disturbance over 1 acre additionally triggers the state CDPHE stormwater permit described above. New single-family homes with driveway disturbance under 0.5 acre can typically use a simplified Notice of Intent instead of a full permit. Jefferson County Engineering & Earthwork: (303) 271-8700.
Broomfield
Broomfield is both a city and a county, so one department handles both. Grading over 5,000 cubic yards triggers additional requirements under IBC Appendix J, and permit fees are tiered by cubic yardage well below that threshold — there is no published small-residential exemption. Broomfield Engineering Division: (303) 438-6380, engineeringpermits@broomfield.org.
Arapahoe County (Unincorporated)
For unincorporated Arapahoe County (relevant near Centennial), a standard Grading/Erosion/Sediment Control (GESC) Permit is required for land-disturbing activity per the county's GESC Manual, with a "Low Impact" GESC Permit available where disturbance is under 1 acre. We could not verify a specific small cubic-yard exemption on the county's own site — treat any number you see elsewhere online for Arapahoe County as unconfirmed until you check with the department directly. Arapahoe County Engineering Services: (303) 795-4400.
Aurora
Aurora requires a stormwater quality/erosion-control permit before any site disturbance that removes vegetation, regardless of volume. A narrower 50-cubic-yard exemption exists in Aurora's code, but it applies specifically to gravel-extraction and mineral-exploration activity — don't assume it extends to general residential fill. Aurora Permit Center: (303) 739-7420.
Parker
Parker requires a grading permit under Municipal Code Chapter 11.10 for qualifying earthwork. We were not able to confirm a specific cubic-yard threshold from a machine-readable source, so if your project is more than a small yard-fill, call ahead. Parker Public Works: (303) 840-9546.
Denver, Lakewood, Arvada, Westminster, Thornton, Centennial, Highlands Ranch/Douglas County, Longmont, Castle Rock, Commerce City, Littleton, and Golden
We could not find a publicly published small-residential cubic-yard exemption for any of these jurisdictions. That doesn't necessarily mean no threshold exists — it means it isn't published in a form we could verify, so we're not going to guess at a number. You'll see a "300 cubic yards / 3 feet" figure repeated on some secondary sources for Denver-area cities; that number comes from the baseline IBC Appendix J model code language, not a confirmed local amendment, so don't rely on it without checking your city's actually-adopted grading ordinance. If your project is a small residential yard-leveling or backfill job, it's very likely exempt from formal review everywhere on this list — but for anything approaching 50+ yards, foundation-adjacent work, or floodplain-adjacent property, call your city's building or engineering department before ordering.
Highlands Ranch is a special case worth calling out again: it has no independent city government, so permits go through Douglas County Community Development rather than a "Highlands Ranch" building department.
What This Means If You're Just Leveling a Yard
The overwhelming majority of residential deliveries we make across the Denver metro — yard leveling, foundation backfill after a repair, a pool fill — are well under every threshold listed above, city or county. Permits become a real question at commercial scale, subdivision grading, anything near a mapped floodplain, or projects pushing past 50 cubic yards in Boulder-area jurisdictions specifically. When in doubt, a two-minute call to your city or county's building/engineering department before you order saves a lot more time than finding out after the fact.
How We Help
We deliver fill dirt — we don't issue or track permits. But we've delivered across every jurisdiction on this list and can tell you whether a project like yours typically needs one in our experience. Text us at (720) 577-5016 with your project details and city, and we'll point you toward the right department if you're not sure. Always confirm the final answer with your specific city or county — this article reflects what each jurisdiction had published as of August 2026, and local codes do change.