Can I build an ADU on a Castle Rock townhome lot?
✓ Verified against code · August 20, 2026
No. ADUs are barred on lots with an existing duplex, triplex, condominium, townhome or multifamily use, and in the MH district entirely. The rule is one ADU per lot or tract, accessory to a single-family home.
Citation: CRMC §17.61.040; §17.61.050(C)(1)
How current is this?
Castle Rock’s ADU rules run under CRMC Ch. 17.61 (Accessory Dwelling Units) (Ordinance 2025-023). Castle Rock is bound by HB24-1152 through DRCOG. Ordinance 2025-023 took effect July 1, 2025, one day after the statute's June 30 deadline — a timing note rather than evidence of anything, since the deadline governed filing rather than the effective date of local code. That ordinance made a real change: the original 2017 ADU ordinance imposed a genuinely ongoing occupancy obligation, and the current code checks residency only once, when you apply. We verified this answer against primary sources on August 20, 2026, and every change we catch is logged in the changelog.
More Castle Rock ADU questions
- Do I have to live on the property in Castle Rock?
- How big can a Castle Rock ADU be?
- Do I need parking for a Castle Rock ADU?
- Does my Castle Rock ADU have to match my house?
All Castle Rock ADU rules → · Compare Colorado cities →
Not legal advice — lot-specific overlays can change the answer for your parcel. The citation above points at the governing code section; check it, or ask the city to confirm.