# Building permits at 3621 21st St, Boulder, CO 14 permits on record here. The newest, Jun 24: Boiler replacement PLEASE NOTE: APPLICABLE ONLY TO SYSTEMS WITH FUEL BURNING APPLIANCES: All new plastic. Boulder publishes permits without map coordinates, so this address has no map and no quarter-mile list. ## At this address | Date | Type | Work | Cost | Permit | |---|---|---|---|---| | Jun 24, 2026 | Mechanical (HVAC) | Boiler replacement PLEASE NOTE: APPLICABLE ONLY TO SYSTEMS WITH FUEL BURNING APPLIANCES: All new plastic glued vents for fuel burning appliances must undergo pressure testing. To facilitate the inspection process, please provide photographic evidence of the pressure test directly to the assigned ins | $10,772 | [MEC2026-01044](https://nearbypermits.com/boulder/permit/MEC2026-01044/) | | Aug 18, 2021 | Fire systems | NFPA 13D pump and tank wet fire sprinkler system for a New 7948 sf 2-story single family detached dwelling with basement and attached garage. Basement: 2538 sf (1031 sf finished). 1st Floor: 3067 sf w/ 978 sf attached garage. 2nd Floor: 1365 sf. See BLD-SFD2020-00295 for general building permit. Mar | $22,700 | [FIR2021-00278](https://nearbypermits.com/boulder/permit/FIR2021-00278/) | | Jan 8, 2021 | Pool or spa | * New 13'-10" x 41'-11" In-ground concrete pool, 580ft² total. Pool equipment located in new building construction via permit BLD-ACC2020-00130. All other site considerations including energy offsets fulfillment, subcontractors, storm water calculation worksheet, plumbing fixture count, site grading | $198,590 | [BLD-ACC2020-00158](https://nearbypermits.com/boulder/permit/BLD-ACC2020-00158/) | | Dec 3, 2020 | Plumbing | *Construction of a new accessory building for an indoor swimming pool (pool under separate permit). Building will be 106 sf and unconditioned, with exception of a half bath. | $5,500 | [PLB2020-00489](https://nearbypermits.com/boulder/permit/PLB2020-00489/) | | Dec 3, 2020 | Electrical | *Construction of a new accessory building for an indoor swimming pool (pool under separate permit). Building will be 106 sf and unconditioned, with exception of a half bath. | $5,000 | [ELE2020-01043](https://nearbypermits.com/boulder/permit/ELE2020-01043/) | | Dec 3, 2020 | New building | *Construction of a new accessory building for an indoor swimming pool (pool under separate permit). Building will be 106 sf and unconditioned, with exception of a half bath. | $100,000 | [BLD-ACC2020-00130](https://nearbypermits.com/boulder/permit/BLD-ACC2020-00130/) | | Nov 24, 2020 | Fence, wall or deck | *Poured concrete wall with piers, shingle cladding, on east side of pool bldg. Height not to exceed 7 feet, approximately 56 feet in total length. | $17,000 | [FEN2020-00046](https://nearbypermits.com/boulder/permit/FEN2020-00046/) | | Nov 23, 2020 | Plumbing | *New 7948 sf 2-story single family detached dwelling with basement and attached garage. Basement: 2538 sf (1031 sf finished). 1st Floor: 3067 sf w/ 978 sf attached garage. 2nd Floor: 1365 sf. | $34,500 | [PLB2020-00457](https://nearbypermits.com/boulder/permit/PLB2020-00457/) | | Nov 23, 2020 | Mechanical (HVAC) | *New 7948 sf 2-story single family detached dwelling with basement and attached garage. Basement: 2538 sf (1031 sf finished). 1st Floor: 3067 sf w/ 978 sf attached garage. 2nd Floor: 1365 sf. | $163,500 | [MEC2020-01086](https://nearbypermits.com/boulder/permit/MEC2020-01086/) | | Nov 23, 2020 | Electrical | *New 7948 sf 2-story single family detached dwelling with basement and attached garage. Basement: 2538 sf (1031 sf finished). 1st Floor: 3067 sf w/ 978 sf attached garage. 2nd Floor: 1365 sf. | $65,500 | [ELE2020-00976](https://nearbypermits.com/boulder/permit/ELE2020-00976/) | | Nov 23, 2020 | New building | *New 7948 sf 2-story single family detached dwelling with basement and attached garage. Basement: 2538 sf (1031 sf finished). 1st Floor: 3067 sf w/ 978 sf attached garage. 2nd Floor: 1365 sf. | $2,200,000 | [BLD-SFD2020-00295](https://nearbypermits.com/boulder/permit/BLD-SFD2020-00295/) | | Sep 29, 2020 | Electrical | *Installation of a 16.125 kW grid-tied, flush-mount rooftop solar PV system. No batteries or service change.* Resubmittal received on 6/3: We are increasing the PV system size to 19.500kW. The new design plans are attached- Materials will stay the same. | $33,832 | [ELE2020-01289](https://nearbypermits.com/boulder/permit/ELE2020-01289/) | | Jul 6, 2020 | Electrical | *Single family residence, complete demolition, and then a new build. | Not listed | [ELE2020-00893](https://nearbypermits.com/boulder/permit/ELE2020-00893/) | | Jun 18, 2020 | Demolition | Full structure demolition of a single family detached dwelling with attached garage built in 1968. | Not listed | [DEM2020-00028](https://nearbypermits.com/boulder/permit/DEM2020-00028/) | ## Zoning requests nearby We don't list zoning cases for Boulder yet. Look them up on the city's Board of Zoning Adjustment page: https://bouldercolorado.gov/government/board-commission/board-zoning-adjustment ## More on this street Other addresses on 21st St with permits, nearest house number first: - [3633 21st St](https://nearbypermits.com/boulder/address/3633-21st-st/): newest permit Oct 10, 2024 - [3639 21st St](https://nearbypermits.com/boulder/address/3639-21st-st/): newest permit Dec 6, 2024 - [3867 21st St](https://nearbypermits.com/boulder/address/3867-21st-st/): newest permit May 4, 2026 - [2980 21st St](https://nearbypermits.com/boulder/address/2980-21st-st/): newest permit Jul 20, 2026 - [2941 21st St](https://nearbypermits.com/boulder/address/2941-21st-st/): newest permit Nov 18, 2025 - [2921 21st St](https://nearbypermits.com/boulder/address/2921-21st-st/): newest permit Oct 7, 2025 - [2881 21st St](https://nearbypermits.com/boulder/address/2881-21st-st/): newest permit Sep 23, 2026 - [2860 21st St](https://nearbypermits.com/boulder/address/2860-21st-st/): newest permit Aug 18, 2026 - [2820 21st St](https://nearbypermits.com/boulder/address/2820-21st-st/): newest permit Jul 28, 2026 - [2327 21st St](https://nearbypermits.com/boulder/address/2327-21st-st/): newest permit Aug 25, 2026 --- Source: Boulder Planning and Development Services permit data (https://www.arcgis.com/home/item.html?id=e3ff6248e4a547bcba31025d2c5c9fee). Checked 2026-10-10 18:25 UTC. Nearby Permits, https://nearbypermits.com. JSON API and MCP server: https://nearbypermits.com/developers/ All 14 permits at this address: https://nearbypermits.com/boulder/address/3621-21st-st/