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Centennial’s high-value homes, DTC proximity, and strong rental market make it one of the best suburban ADU investments in the south metro. Here’s what you need to know.
| ADUs Allowed? | ✅ Yes — subject jurisdiction under HB 24-1152 |
| 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 |
| Short-Term Rental (STR)? | Arapahoe County STR rules apply; verify current ordinance |
| Permit Path | Administrative approval through Centennial/Arapahoe County |
| Estimated Permit Timeline | 8–14 weeks |
| Official Source | City of Centennial Development Services |
⟳ Last reviewed: October 2026. ADU rules change. Always verify current code with Centennial before starting a project. View official source →
Centennial is an affluent Arapahoe County suburb with 110,000 residents, high home values, and large lots — but it has virtually zero ADU competition online. Older homes in Centennial (1970s–1990s) often have generous rear yards and established utility infrastructure, making detached ADU construction relatively straightforward. The city’s contract relationship with Arapahoe County for some services means permit routing can vary — confirm the right department before submitting.
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 | $205,000–$380,000 |
| Garage Conversion | $52,000–$138,000 |
| Basement ADU Conversion | $40,000–$110,000 |
| Permit Fees (estimate) | $3,000–$9,000 (Arapahoe County/Centennial Development Services) |
| Utility Tap Fees (detached) | $5,000–$15,000 (South Suburban Water and Sanitation or other Arapahoe County districts) |
| Estimated Monthly Rent | $1,750–$2,900/month |
| Estimated Break-Even | 7–11 years for detached; 3–5 years for conversion |
Local note: Centennial’s large older lots in established neighborhoods often have favorable site conditions for detached ADUs. Utility district boundaries vary by neighborhood — confirm your provider before budgeting tap fees.
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.