Building on your own Boulder property may not need a contractor license, but the city limits it to one structure a year and the county runs separate rules.
A homeowner in Boulder who builds on their own property can often skip a contractor license, but the exemption is narrower than most owners expect. The City of Boulder limits it to one building or structure per calendar year and asks for a separate homeowner contractor application. Boulder County, which covers the unincorporated area, uses its own contractor classes and its own list of people who are not contractors. This guide explains both, plus where the State of Colorado steps in for electrical and plumbing work.
At a glance
- The City of Boulder excludes a homeowner working on their own residence or an accessory structure for personal use, but only for one building or structure per calendar year.
- The city lists a separate Homeowner Contractor application, and other work must be done by a licensed general contractor.
- Boulder County lists the property owner, and anyone doing labor or repair work on their own property, as not being a contractor.
- Electrical and plumbing contractors are licensed by the State of Colorado, not the county.
- County contractor license fees run from $150 to $350 depending on the class.
For the statewide picture, read the Colorado contractor license guide. For three other Front Range cities, see the Colorado homeowner permit rules for Denver, Fort Collins and Centennial. This page covers Boulder city and county.
City of Boulder versus Boulder County
Boulder has two separate rule sets, and the one that applies depends on where your lot sits. Inside city limits, the City of Boulder Planning and Development Services office licenses contractors under Chapter 4-20 of the Boulder Revised Code. In unincorporated Boulder County, the county licenses contractors by class. Check your property's jurisdiction before you read further, because a license from one does not answer to the other's rules.
| Question | City of Boulder | Boulder County |
|---|---|---|
| Who licenses building contractors? | City, classes A through G plus homeowner contractor | County, classes A, B, C, M plus roofing and mechanical |
| Homeowner exemption? | One building or structure per calendar year | Owner and owner labor listed as not contractors |
| Electrical and plumbing | State of Colorado | State of Colorado |
| Fee amounts on the page | None listed, see schedule of fees | Listed by class |
The City of Boulder homeowner exception
The city's contractor licensing page says a homeowner who works on their own residence, or on an accessory structure for personal use, is excluded from the definition of a contractor. The page then adds the limit: this exception is available only as to one such building or structure during a calendar year. Other work must be performed by a licensed general contractor.
The page also lists a Homeowner Contractor License application as its own item, so an owner should not assume the exclusion works without paperwork. Building and mechanical permits cannot be issued to unlicensed persons, with one exception: a homeowner working on their own home.
Plumbing, mechanical and fire
The city's definitions of plumbing, mechanical and fire contractors each exclude homeowners working on their own residence or on accessory structures for personal use. The exclusion covers the owner. It does not cover a friend, a relative or a handyman who does the work for you.
Electrical
The page does not state a homeowner exception for electrical work. The city's electrical registration, which carries no fee, applies to people the state requires to be licensed. Because the page is silent, ask the city before you plan any wiring.
Boulder city license classes
When the homeowner exemption does not fit, the city offers these classes.
| Class | Scope listed by the city |
|---|---|
| A, B and C | General contractors |
| D-1 through D-9 | Specialty trades |
| E | Fences and minor structures |
| F | Owner's own building, up to $500 in labor and materials |
| Mechanical | Classes A through E |
Class A, B and C applicants need an ICC certificate. Class A and B applicants must also show education, training or experience in non-residential construction. The city page gives no fee amounts. It points to the Planning and Development Services Schedule of Fees, which is updated annually.
Boulder County contractor licenses
Boulder County's contractor licensing page says the following are not considered contractors: the property owner, and a person performing labor or repair work on their own property. It also states that plumbers and electricians are licensed by the State of Colorado, not the county.
The county issues these classes and fees.
| License class | Scope | Licensing fee |
|---|---|---|
| Class A | Commercial construction | $350 |
| Class B | Commercial remodeling or tenant finish | $300 |
| Class C | One and two family residential | $250 |
| Residential mechanical | Residential mechanical work | $175 |
The county also licenses commercial mechanical work at $200, roofing at $150 and Class M at $150. Class M covers work such as deconstruction, masonry, grading and excavation, window replacements and re-siding. Applicants show proof of passing the applicable ICC exam. Fees are set by the county and can change. Verify the current amount with the provider before you pay.
The county page does not say whether the owner exclusion applies to permits or to a particular type of project. For that question, email contractorlicensing@bouldercounty.gov or call 303-441-3930.
The state side: electrical and plumbing permits
The Colorado Division of Professions and Occupations runs a permit system for electrical and plumbing work in places that do not run their own program. Its page says that if you hire an electrical or plumbing contractor, the contractor must get the permit and you should not continue with the permit application as the homeowner. It also says it is a violation of state law for anyone other than the homeowner who is not a registered contractor to install a project on your property.
Boulder appears on the state's list of local jurisdictions for both electrical and plumbing, so the state does not inspect there and you must work with the local authority. If you are in a jurisdiction the state covers, a separate permit is required for each detached structure on the same property, and an adult homeowner or the homeowner's representative must be present at an inspection of an occupied dwelling. The page does not say whether a homeowner may personally perform the work, so confirm that with the division at 303-894-7800.
Questions to settle before you start
- Is the property inside the City of Boulder or in unincorporated Boulder County?
- Is this the only building or structure you will build on this property this calendar year?
- Is the work on your own residence or an accessory structure for your own use?
- Will anyone other than you do any of the work?
- Does the job include electrical or plumbing work, which the state licenses?
If the answer to the fourth question is yes, plan to hire a licensed contractor for that portion. A homeowner exemption protects the owner's own labor, not a hired crew.
Where the homeowner path stops
The exclusion exists for a person improving their own home. If you build to sell, build for others or run projects as a business, you are acting as a contractor, and the city or county expects a license that fits the work. When a project grows past one structure a year, the owner path closes.
When a company needs a qualifier
Contractors who work in Boulder and elsewhere along the Front Range deal with local licenses on top of state electrical and plumbing licenses. A company often has to name a qualified individual who holds the credential. A qualifying agent QUALIFIES a company, working as a full time W-2 employee of the company they qualify.
Read What Is a Qualifying Agent for the basics and contractor license vs business license for how the two credentials differ. Founders Marshall Schofield and Jeremiah Jaskulski built The Licensing Company to help contractors in exactly this position. If your plans are bigger than one house, see Hire a Qualifying Agent and consultation packages.
For the trade ladders behind the state licenses, see electrician license Colorado and plumbing license Colorado.
FAQ
Can I build my own house in Boulder without a contractor license? The city excludes a homeowner working on their own residence, limited to one building or structure per calendar year, and lists a separate Homeowner Contractor application. Confirm the process with the city before you file.
Does Boulder County license homeowners? The county lists the property owner, and a person doing labor or repair work on their own property, as not being contractors.
Who licenses electricians and plumbers in Boulder? The State of Colorado, not the county.
What does a Boulder County Class C license cost? The county page lists a $250 licensing fee for Class C, one and two family residential. Fees can change, so verify with the county.
How much does it cost to hire a qualifying agent? It depends on the state, the trades, the company's structure and the scope of work, so there is no flat number. See consultation packages to discuss your situation.
Sources
- City of Boulder, Contractor Licensing, read 2026-10-31
- Boulder County, Contractor Licensing, read 2026-10-31
- Colorado Division of Professions and Occupations, Electrical and Plumbing Permits, read 2026-10-31
Rules change and offices update forms. Confirm the current requirements with the City of Boulder or Boulder County before you start work.
Disclaimer: This article is provided for educational and informational purposes only. It does not constitute legal advice, licensing guidance, or an offer of services. Licensing requirements vary by jurisdiction. For specific compliance questions, contact The Licensing Company for a confidential consultation.