Boulder building & ADU permits
Recent permit activity, updated continuously.
Boulder lies northwest of Denver and is home to the University of Colorado. Under Colorado's HB24-1152, larger Front Range cities must allow ADUs. Boulder publishes its construction permits under CC0 and even carries an 'accessory' building-permit type, which Igni uses to help identify ADU activity.
Igni is tracking 591 residential and building permits in Boulder, CO — including 24 classified accessory-dwelling-unit (ADU) filings. The most active ZIP is 80304. The most recent filing Igni tracked was Sep 16, 2026. All records come from City of Boulder open data (ArcGIS), an official government open-data feed, and are refreshed continuously.
591
Permits tracked
24
ADU permits
5
Distinct ZIP codes
Sep 16, 2026
Newest permit
Recent permits
A sample of the freshest permits in this jurisdiction — ZIP and city only (no street addresses).
| ZIP | Permit type | ADU type | Valuation | Applied |
|---|---|---|---|---|
| 80305 | Residential | — | $160,000 | Sep 16, 2026 |
| 80305 | Residential | — | $30,000 | Sep 16, 2026 |
| 80305 | Residential | — | $8,123 | Sep 16, 2026 |
| 80303 | Residential | — | $3,247 | Sep 16, 2026 |
| 80301 | Residential | — | $7,264 | Sep 16, 2026 |
| 80304 | Residential | — | $12,636 | Sep 15, 2026 |
| 80305 | Residential | — | $9,000 | Sep 15, 2026 |
| 80302 | Residential | — | $29,256 | Sep 15, 2026 |
| 80302 | Residential | — | $1 | Sep 15, 2026 |
| 80305 | Residential | — | $5,500 | Sep 15, 2026 |
| 80302 | Commercial | — | $225,000 | Sep 15, 2026 |
| 80304 | Residential | Detached ADU | $50,149 | Sep 15, 2026 |
| 80303 | Residential | — | $100,700 | Sep 15, 2026 |
| 80305 | Residential | — | $821 | Sep 8, 2026 |
| 80301 | Commercial | — | $8,300,000 | Sep 8, 2026 |
| 80304 | Residential | — | $25,000 | Sep 8, 2026 |
| 80301 | Commercial | — | $600,000 | Sep 9, 2026 |
| 80305 | Residential | — | $120,000 | Sep 9, 2026 |
| 80301 | Residential | — | $3,333 | Sep 10, 2026 |
| 80302 | Residential | — | $23,000 | Sep 10, 2026 |
Top ZIP codes by recent activity
ADU types in the recent set
Housing law — Colorado
Colorado's HB24-1152 (2024) requires larger Front Range municipalities to allow at least one accessory dwelling unit, by administrative approval, wherever single-family homes are permitted — generally from June 30, 2025.
HB24-1313 (2024) requires qualifying transit-oriented communities to plan for greater housing density near rail and frequent-bus corridors, rather than imposing a statewide duplex mandate.
Boulder ADU rules
Boulder overhauled its accessory dwelling unit rules with Ordinance 8650, which applies to ADU proposals submitted on or after March 8, 2025, and brought the city in line with Colorado's House Bill 24-1152 — the 2024 state law requiring larger Front Range jurisdictions to allow an ADU wherever single-family homes are permitted. The new rules eliminated several long-standing Boulder barriers: the owner-occupancy requirement, parking minimums, minimum lot size, side-entrance screening, and the neighborhood 'saturation' cap that had limited how many ADUs a given area could have.
For a market-rate ADU, Boulder generally allows up to 800 square feet for a detached unit or 1,000 square feet for an attached unit (or 50 percent of the primary structure's footprint, whichever is less). The city offers a larger envelope — up to 1,000 square feet detached or 1,200 square feet attached — for a deed-restricted affordable ADU, in exchange for a rent cap aimed at households at 75 percent of area median income.
With owner-occupancy and the saturation cap gone, a code-compliant ADU is now far more broadly available across Boulder's residential lots than under the old code. Colorado's HB 24-1152 took effect statewide on June 30, 2025.
This is an informational summary — verify current rules with the city's planning/permitting department; not legal advice.
See also: Colorado ADU law and what is an ADU?
Data source
Sourced from City of Boulder open data (ArcGIS). CC0 — public domain (commercial use permitted).
Nearby cities — Colorado
Learn more about ADUs & building permits
Background reading on accessory dwelling units, building permits, and how Igni turns Boulder permit records into leads.
Boulder permit data — FAQ
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Informational only, not legal advice. Headline counts reflect all permits Igni has tracked for this jurisdiction; the table shows recent activity. Housing law changes — verify current statutes before relying on this.