ADU Ledger

How big can an Arvada ADU be?

✓ Verified against code · August 19, 2026

It depends on your lot: 600 sq ft on lots up to 6,000 sq ft, stepping up to 1,200 sq ft on lots over an acre — but never more than 40% of the home's living space. Note the small-lot cap conflicts with the state statute's 750 sq ft protection, which is part of the state's non-compliance finding.

Citation: LDC Table 5-1-5-2

How current is this?

Arvada’s ADU rules run under Land Development Code §5-1-5-2 (2022 LDC (Ord 4793), amended by Ord 4905). Arvada's ADU framework dates to its 2022 code and was amended in August 2025 — after the state deadline — without fixing the provisions that appear to conflict with Colorado's ADU statute: ongoing owner-occupancy with a deed restriction, a blanket parking mandate, and size caps that dip below the statute's protected range. The state's October 2025 compliance review listed Arvada among the non-complying jurisdictions. We verified this answer against primary sources on August 19, 2026, and every change we catch is logged in the changelog.

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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.