Colorado · Penalties if you skip one
What you can build without a permit in Colorado
By Mario Bailey Last checked · 16 official sources
Quick answer
Across the 3 Colorado jurisdictions we have verified, 1 of 30 project rules need no permit at all, 13 turn on a size or scope condition the jurisdiction publishes, and 16 require a permit regardless. Fence work is where the answer most often comes with a published condition rather than a flat yes: 3 of the 3 jurisdictions that answer publish one. The numbers are not statewide: fence thresholds alone run from 4 to 7 feet depending on the jurisdiction.
How to read this page
"No permit" means the jurisdiction publishes that the work needs no building permit. "Depends" means it publishes a size, height, depth, cost or scope condition that decides the answer, quoted in its own words in the last column; the number beside it is the figure that condition turns on, and which side of the number is exempt is stated by the condition, not by us. Exempt from a building permit is not exempt from zoning, setbacks, height limits, flood rules, an HOA, or a separate electrical, plumbing or mechanical permit, and several of the conditions below say exactly that.
Fence
Jefferson County requires no fence permit at all. 2 of 3 make the fence answer turn on a size or scope condition the jurisdiction publishes, and the 2 that state a number publish figures from 4 to 7 feet.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Jefferson County | No permit | Jefferson County does not require a permit for fences of any height in unincorporated Jefferson County. | |
| Aurora | Depends | 7 feet | fence height at which a building permit is required. |
| Denver | Depends | 4 feet | fences shorter than 4 ft require no permit; fences 4 ft or taller require at minimum a zoning permit; most fence types over 4 ft also require a building permit. |
Patio
All 3 make the patio answer turn on a size or scope condition the jurisdiction publishes.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Aurora | Depends | 30 inches | height above grade of an uncovered concrete patio at which a permit is required. |
| Denver | Depends | covered patios always require a zoning and building permit; uncovered ground-level patios may not require a permit. | |
| Jefferson County | Depends | Ground-level concrete or paver patios are treated like the exempt concrete pads on the Decks page and do not need a Building Permit; patio covers, roofed patio structures, and patio enclosures (anything that adds a roof or walls) need a Building Permit. |
Deck
2 of 3 make the deck answer turn on a size or scope condition the jurisdiction publishes, and the 2 that state a number publish figures from 12 to 30 inches. Jefferson County requires a permit for deck work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Aurora | Depends | 30 inches | deck height above grade at which a permit is required regardless of whether the deck is attached to the house. |
| Denver | Depends | 12 inches | uncovered decks under 12 in off the ground require no permit; 12 in or more requires a zoning permit; 30 in or more also requires a building permit. |
| Jefferson County | Permit required | No exemption by height or size: a Building Permit is required for new decks, deck expansions, replacement decks, and deck repairs. Only a ground-level concrete pad, rather than an elevated deck, avoids the permit. |
Shed
2 of 3 make the shed answer turn on a size or scope condition the jurisdiction publishes, and the 3 that state a number publish figures from 120 to 200 sq ft. Jefferson County requires a permit for shed work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Aurora | Depends | 120 sq ft | shed floor area at which a building permit is required. |
| Denver | Depends | 200 sq ft | sheds up to 200 sq ft with 8 ft top plate and 14 ft max height do not require a building permit but may require a zoning permit in some zone districts. |
| Jefferson County | Permit required | 120 sq ft | Sheds, mini-structures, and shipping containers 120 sq ft or less that sit at least 10 feet from any occupied structure and are no more than 14 feet tall need only a Miscellaneous Permit; anything larger, taller, or closer than 10 feet to an occupied structure needs a full Building Permit instead. Some permit is required at every size. |
Electrical
1 of 3 makes the electrical answer turn on a size or scope condition the jurisdiction publishes. Denver and Jefferson County require a permit for electrical work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Aurora | Depends | An electrical permit is required in Aurora for any service change and for modifications to the electrical system, but the city publishes a real like-for-like exemption: repairing or replacing existing switches, outlets, light fixtures, smoke detectors and carbon monoxide detectors needs no permit unless a new device is installed where none existed. | |
| Denver | Permit required | An electrical permit is required in Denver for all residential electrical work including service installations, panel and subpanel work, interior and exterior wiring, EV chargers, and solar systems. | |
| Jefferson County | Permit required | Jefferson County Building Safety issues Electrical Permits, including for photovoltaic solar work, as one of its standard online permit categories for residential projects. |
HVAC
1 of 3 makes the HVAC answer turn on a size or scope condition the jurisdiction publishes. Denver and Jefferson County require a permit for HVAC work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Aurora | Depends | Aurora requires a mechanical permit for essentially all fixed heating and cooling work: central air conditioning, furnace replacements, evaporative coolers, boilers and gas piping are all listed as 'Always'. The exceptions are narrow and specific, namely a window air conditioner, which needs no permit unless it is hard-wired, and humidifier installations, which need none at all. | |
| Denver | Permit required | A mechanical permit is required in Denver for all residential HVAC work including installation, replacement, and ductwork modifications. | |
| Jefferson County | Permit required | Jefferson County Building Safety issues Mechanical Permits, which cover HVAC equipment, as one of its standard permit categories, including online applications for water heater and wood-burning or solid-fuel fireplace mechanical work. |
Plumbing
1 of 3 makes the plumbing answer turn on a size or scope condition the jurisdiction publishes. Denver and Jefferson County require a permit for plumbing work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Aurora | Depends | Aurora requires a plumbing permit for modifications to the plumbing system and always for a water heater replacement, with a set of published fixture-swap exemptions: toilets and sinks need no permit unless piping is installed or moved or in-wall pipes are touched, sewer line repairs need none unless new piping is installed, and water line repairs need none if the repair is considered minor. | |
| Denver | Permit required | A plumbing permit is required in Denver for all residential plumbing work including fixture installation, water service, water heaters, backflow preventers, and gas piping. | |
| Jefferson County | Permit required | Jefferson County Building Safety issues Plumbing Permits as one of its standard permit categories; water heater plumbing permits can be applied for online, and the building code supplement confirms separate plumbing permits are required even for structures exempt from a Building Permit. |
Pool
1 of 3 makes the pool answer turn on a size or scope condition the jurisdiction publishes. Denver and Jefferson County require a permit for pool work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Aurora | Depends | 24 inches | pool depth at which a building permit is required. |
| Denver | Permit required | Permanent residential swimming pools in Denver require a building permit, a zoning permit, and a Sewer Use and Drainage Permit (SUDP). | |
| Jefferson County | Permit required | A Miscellaneous Permit is required for swimming pools of any size, in-ground or above-ground, and related structures such as diving boards and ladders; hot tubs and swim spas do not need this permit. Any electrical work for the pool needs a separate Building Safety electrical permit. |
If the work is already built
Colorado has no single statewide building code, so building permits are issued and enforced locally: counties adopt building codes under C.R.S. 30-28-201, and once a code is adopted, C.R.S. 30-28-205 makes it unlawful to erect, alter, or remodel a structure without first obtaining a permit. Violating a county building code is a civil infraction under C.R.S. 30-28-209, which carries a fine of up to $100 per offense under C.R.S. 18-1.3-503(1.6), with each day counted as a separate offense, and the county can also ask the county court to impose a civil penalty of $500 to $1,000 under C.R.S. 30-28-210, plus up to $100 for each day the violation continues after the court order; an unpaid penalty becomes a lien on the property collected like unpaid taxes.
Colorado penalties, the after-the-fact path, and what the statute actually says
The 30 answered rules come from 16 official sources, each linked from the permit page behind every jurisdiction name. See the full picture for the state on the Colorado permit requirements page, or the national view of which projects need a permit at all on Do you need a building permit?
This page compiles what each Colorado jurisdiction publishes, with a last checked date. It is not legal advice, and a project that is exempt from a building permit can still need zoning approval or a trade permit. Confirm with the office linked from the jurisdiction's page before you build.