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Highlands Ranch sits in unincorporated Douglas County — HOAs govern most lots, and Colorado’s HB 24-1152 changed the rules entirely. Here’s what that means for your property.
| ADUs Allowed? | ✅ Yes — HB 24-1152 overrides prior HOA restrictions |
| Maximum Size | 1,000 sq ft or 50% of primary home area |
| ADU Types Permitted | Detached, attached, basement, garage conversion |
| Owner-Occupancy Required? | Not required under HB 24-1152 |
| Parking Requirement | 1 space per ADU |
| HOA Override? | HOAs cannot prohibit ADUs per HB 24-1152; design standards may still apply |
| Short-Term Rental (STR)? | Douglas County STR rules and HRCA rules apply; verify before renting |
| Permit Path | Douglas County Building Division; administrative approval for compliant ADUs |
| Estimated Permit Timeline | 10–16 weeks; HRCA design review may add 2–4 weeks |
| Official Source | Douglas County Planning & Community Development |
⟳ Last reviewed: October 2026. ADU rules change. Always verify current code with Highlands Ranch before starting a project. View official source →
Highlands Ranch is one of the best ADU markets in Colorado despite its HOA-heavy reputation. HB 24-1152 directly addressed the HOA prohibition issue that previously blocked most projects here. The community’s 105,000 residents, high household incomes, large walk-out lots, and established neighborhood desirability make ADU rental income strong. The HRCA (Highlands Ranch Community Association) still has architectural standards, but they cannot prohibit your ADU — they can only regulate aesthetics like materials and colors.
Not sure if your lot qualifies? The ADU quiz takes 3 minutes and gives you a personalized eligibility summary based on your property type, location, and goals. Take the free ADU quiz →
| Detached Backyard Cottage | $210,000–$390,000 |
| Garage Conversion | $55,000–$140,000 |
| Basement ADU Conversion | $42,000–$115,000 |
| Permit Fees (estimate) | $3,000–$9,000 (Douglas County Building Division) |
| Utility Tap Fees (detached) | $5,000–$15,000 (Centennial Water and Sanitation District) |
| Estimated Monthly Rent | $1,800–$3,000/month |
| Estimated Break-Even | 7–11 years for detached; 3–5 years for walk-out basement |
Local note: HRCA architectural review typically adds 2–4 weeks and a review fee ($200–$500) but rarely adds construction cost. Walk-out basements on sloped lots are the most common and cost-efficient ADU path here.
Cost ranges reflect 2026 Denver metro construction pricing. Individual project costs depend on site conditions, finishes, utility distances, and contractor selection. Get multiple bids before committing to a budget.
Official Sources
Rules and fees change. Always verify current requirements directly with your local jurisdiction and utility provider before starting a project.
Answer 7 questions to see your estimated cost range, likely ADU type, and local eligibility — free, no sign-up required.