ADU / Guest House · Highlands Ranch, Douglas County, Colorado

ADU / Guest House Build Contractor in Highlands Ranch

Brothers 59 Construction delivers accessory dwelling unit in Highlands Ranch — master-planned suburbs with open-space corridors. Typical project range $800K–$3M; two-story and main-floor primary estate homes. 5.0/5 rating across 19 verified Google reviews.

Phone: 303-434-7658 · Email: michaelglivar1@gmail.com

Cost Guide

ADU / Guest House Build Cost in Highlands Ranch, Douglas County (2026)

TierInvestment RangeWhat's Included
Refined$350,000–$600,000600–900 sq ft detached guest house with full kitchen, bath, and finishes matched to the main home
Signature$600,000–$1,100,0001,000–1,500 sq ft ADU with vaulted living space, high-end kitchen, garage bay, and independent utilities
Architectural$1,100,000–$2,000,000+1,500+ sq ft custom guest residence with premium millwork, luxury baths, smart systems, and site-integrated architecture

Where the investment goes: Labor & trades 42–55% · Materials & fixtures 30–42% · Design, permits & mgmt 12–20%.

What drives Highlands Ranch ADU / Guest House cost

ADUs carry a full house's systems on a small footprint, so per-square-foot costs run high—foundations, separate utility connections, and septic capacity (common on Douglas County acreage lots) are major cost centers. Zoning is the biggest variable: Douglas County limits ADU size and requires it to be subordinate to the primary residence, and well/septic permitting through Tri-County Health can add months. Matching the main home's luxury finish level and any required fire-sprinkler systems push the upper tiers.

Scope of Work

ADU / Guest House in Highlands Ranch

Detached and attached ADUs from permit-set through CO: foundations, framing, full MEP, kitchen, bath, and finish package.

Trade Depth & Schedule

Douglas County ADU permitting, utility separation, and code-compliant egress, fire-rating, and energy assemblies.

Specification & Brands

Marvin, Sub-Zero/Wolf compact, Miele, Bosch

Highlands Ranch Communities

Active across Backcountry, BlueSage, Eastridge, Westridge, Northridge, Southridge and surrounding Highlands Ranch neighborhoods, with HOA-compliant design review packages prepared to each ARC standard.

Market Authority

Douglas County Permit Activity

Brothers 59 Construction publishes monthly Douglas County permit reports sourced from official county records.

View the full monthly permit report →
Related Services in Highlands Ranch

Kitchen Remodel in Highlands Ranch → · Bathroom Remodel in Highlands Ranch → · Whole-Home Remodel in Highlands Ranch → · Custom Home Builder in Highlands Ranch → · General Contractor in Highlands Ranch → · Home Addition in Highlands Ranch → · Basement Finishing in Highlands Ranch → · Primary Suite Remodel in Highlands Ranch → · Outdoor Living in Highlands Ranch → · Wellness Suite in Highlands Ranch → · Smart Home Automation in Highlands Ranch → · Wine Cellar in Highlands Ranch → · Home Theater in Highlands Ranch → · Pool & Spa in Highlands Ranch → · Auto Gallery in Highlands Ranch →

ADU / Guest House in Nearby Douglas County Communities

ADU / Guest House in Lone Tree → · ADU / Guest House in Larkspur → · ADU / Guest House in Sedalia → · ADU / Guest House in Franktown →

FAQ

ADU / Guest House in Highlands Ranch — Frequently Asked

Are ADUs allowed in Douglas County?

Yes, but with restrictions—size is typically capped relative to the main home, only one ADU per lot is permitted in most zones, and rural lots must verify well and septic capacity before approval; we handle the full zoning and permitting review up front.

Do I need a separate septic system for a guest house?

Often yes on unincorporated acreage; either your existing system must be re-engineered for the added load or a new field installed, which can add $30,000–$75,000 and requires Tri-County Health approval.

Can an ADU be rented out?

Long-term rental of a permitted ADU is generally allowed, but short-term rental rules vary by community and HOA—we recommend confirming current Douglas County and covenant restrictions during planning.

Contact

Start Your Highlands Ranch ADU / Guest House Build Project

Phone: 303-434-7658 · Email: michaelglivar1@gmail.com