How Much Does It Cost to Build an ADU in Arvada?

Arvada homeowners are seeing a massive shift in property potential this year. The recent state laws have transformed accessory dwelling units from a rare luxury into a standard option for almost any single-family lot. From what I have seen locally, figuring out the true adu cost Arvada requires is now the most important first step.

We at Arvada Remodeling Pros have spent years transforming homes and building functional spaces throughout the Greater Denver area, including full home addition and ADU construction. This guide breaks down the true 2026 accessory dwelling unit cost Arvada homeowners can expect. Let’s look at the data, what it actually means for your wallet, and explore practical ways to plan a successful build.

What ADU cost Arvada builders quote (by type)

Our 2026 pricing data shows Arvada accessory dwelling units fall into four distinct categories with unique financial profiles. A basic garage conversion will run between $60,000 and $120,000. This initial ADU price Colorado contractors quote depends heavily on the existing foundation and utility access.

We typically quote detached new construction between $150,000 and $250,000 or more. Building from the ground up requires extensive site work and brand-new utility lines. The chart below outlines the current pricing landscape for these four common builds so you can set a realistic baseline.

The cost drivers ranked

We rank the project type, utility connections, and structural size as the three largest factors dictating your final invoice. Converting an existing space is always cheaper than pouring a new foundation. The specific details of your lot will trigger different fee structures at the city planning office.

1. Type (conversion vs. new construction)

Our recent estimates show a garage conversion to a 500-square-foot unit typically costs $60,000 to $120,000. The existing footprint gives you a massive financial head start. A new-construction detached unit of the exact same size hits $150,000 to $200,000.

“Converting a structure saves the massive expense of pouring concrete and framing a new roof. It is the fastest path to adding legal square footage.”

We attribute this dramatic price gap entirely to reusing the existing envelope. Ground-up builds demand heavy machinery and extensive site preparation before any actual construction begins.

2. Utility connections and tap fees

Our clients are often caught off guard by the steep utility tap fees required in Jefferson County. Arvada mandates a separate water tap and System Development Charges for certain detached projects. Adding new plumbing fixtures means you must also pay Metro Water Recovery sewer capacity fees before securing your certificate of occupancy.

We strongly advise budgeting $15,000 to $20,000 just for these water and sewer connections on a new detached build. A separate electric meter and dedicated gas service will add another $3,000 to $8,000 to the total. Basement and garage conversions usually avoid this massive expense by sharing existing utilities with the primary residence.

3. Arvada zoning size limits

We always start the design process by checking your specific lot size against the city zoning caps. The Arvada Planning Division scales allowable square footage directly to your property size:

• Lots under 6,000 square feet are capped at a 600-square-foot unit.
• Lots between 6,001 and 12,499 square feet allow up to an 850-square-foot structure.
• Larger residential lots up to an acre can legally support a 1,000-square-foot building.

Our architects must also ensure attached units do not exceed 40 percent of the primary home’s living area. Every additional 100 square feet on a detached build adds roughly $20,000 to $30,000 in material and labor.

4. Finish level and site conditions

We track local material prices closely to understand exactly how interior selections impact the budget. Basic builder-grade materials like standard fiberglass showers keep costs low, while custom ceramic tile and solid wood cabinetry will push the price up by 15 to 25 percent on the exact same floor plan. A flat backyard with easy alley access makes the construction phase incredibly fast and cheap.

Our crews have to factor in an extra 10 to 15 percent for foundation and site preparation if your lot is sloped or rocky. Restricted access that forces teams to haul equipment by hand will also drive up labor hours. Simple logistics play a massive role in the final tally.

What’s included in a typical detached ADU cost

We price a standard $180,000 detached unit in Arvada to be completely move-in ready for a tenant or family member. This figure covers a 600 to 700-square-foot structure finished with durable, mid-range materials. The comprehensive package handles everything from the initial 3D renderings to the final city inspections.

Design, permitting, and structural basics

Our team manages the complex administrative work required by the building department. This includes securing stamped structural plans and filing the mandatory Declaration of Covenants. A true turnkey build starts with these foundational elements:

• Architectural design and stamped structural engineering plans.
• Permit fees and necessary Arvada water tap fees.
• Concrete foundation work, wall framing, and sheathing.
• Complete roofing systems and exterior siding.

Interior finishes and mechanical systems

We ensure the interior is completely finished and ready for occupancy. High-quality spray foam insulation meeting current IECC codes keeps the unit comfortable year-round. The interior package includes the following upgrades:

• Energy-efficient mechanicals like Mitsubishi mini-split HVAC systems.
• Full plumbing setup including a kitchenette and dedicated water heater.
• Electrical panels, wiring, and modern lighting fixtures.
• Drywall, baseboard trim, painting, and durable LVP flooring.
• Kitchen cabinetry paired with solid quartz countertops.

How rental income changes the math

Our local housing data shows that consistent rental income drastically offsets the initial construction shock. Based on current figures, a steady ADU rental income in the Denver metro generates $1,500 to $2,500 a month. The exact rate depends heavily on the square footage, location, and interior quality.

We run conservative math on a $180,000 detached unit renting out for $2,000 monthly. The financials look incredibly strong when mapped out annually for a standard RN-6 zoned property. Here is a realistic breakdown of that investment return:

• Gross annual rent: $24,000.
• Estimated expenses (insurance, property taxes, maintenance): $4,000.
• Net annual income: $20,000.
• Simple payback period: 9 years.
• Effective annual return on build cost: ~11%.

We also remind homeowners that these figures ignore the rapid property appreciation happening across the city. Arvada homes with permitted accessory units are appraising at massive premiums. While the city permits short-term rentals, they restrict permits to just one per lot.

Our financial advice is to decide early if you want to lease the main house or the backyard cottage to tourists. Long-term leasing is often simpler to manage and provides guaranteed monthly cash flow. The economics are increasingly favorable as rents across the Front Range continue to climb.

Where to start

Our team believes the cleanest first step is a free in-home consultation to review your specific property. A quick site visit allows a professional to walk your lot and pull your exact parcel data. Verifying your specific RN-6 or RN-7.5 zoning details takes the guesswork out of the early planning phase.

We run the numbers on maximum lot coverage and required 10-foot corner setbacks to give you a realistic adu cost Arvada builders would actually charge. Getting hard data early prevents expensive redesigns later in the process. Contact us today to see exactly what is possible for your backyard.