The 25 contractors pulling the most building permits in King County, ranked by PermitStack's activity score — built from 121,430 permits on file. Updated from live public records.
| # | Contractor | Permits | Score | Top trades | Last permit |
|---|---|---|---|---|---|
| 1 | WASHINGTON GENERATORS LLC | 27 | 79 | electrical, ev_charger, hvac | Oct 2025 |
| 2 | EPIC PLUMBING LLC | 23 | 75 | fire_alarm, hvac, mechanical | Jun 2026 |
| 3 | JBAR PLUMBING LLC | 21 | 71 | hvac, interior_remodel, plumbing | Apr 2026 |
| 4 | McKinstry Co LLC | 11 | 93 | addition, battery, demolition | Jun 2026 |
| 5 | SMITH FIRE SYSTEMS INC | 8 | 93 | addition, demolition, electrical | May 2026 |
| 6 | Hermanson Company LLP | 8 | 92 | addition, battery, demolition | Jun 2026 |
| 7 | SEATTLE'S PLUMBING LLC | 7 | 51 | hvac, plumbing | Jun 2026 |
| 8 | Northwest Plumbing Connection | 7 | 36 | plumbing | May 2026 |
| 9 | BEST PLUMBING | 6 | 87 | hvac, mechanical, plumbing | Jun 2025 |
| 10 | AMERICAN MECHANICAL | 5 | 84 | electrical, hvac, interior_remodel | Jun 2026 |
| 11 | WOLFE PLUMBING INC | 5 | 83 | electrical, fire_alarm, hvac | Jun 2026 |
| 12 | ACCO ENGINEERED SYSTEMS INC | 4 | 100 | addition, battery, demolition | Jun 2026 |
| 13 | Pye-Barker Fire & Safety, LLC | 4 | 88 | addition, demolition, electrical | Mar 2026 |
| 14 | BEST CHOICE PLUMBING, LLC | 4 | 83 | addition, demolition, new_construction | Apr 2026 |
| 15 | GREENWOOD HEATING AND HOME SERVICES | 4 | 50 | hvac, plumbing | Jun 2026 |
| 16 | PLUMBING JOINT INC | 4 | 34 | plumbing | Jun 2026 |
| 17 | ADVANCED FIRE PROTECTION INC | 3 | 92 | addition, fire_alarm, interior_remodel | Feb 2026 |
| 18 | BEST PLUMBING GROUP LLC | 3 | 82 | addition, fire_alarm, hvac | Apr 2026 |
| 19 | WALTS PLUMBING INC | 3 | 73 | plumbing | Feb 2026 |
| 20 | HAWK MECHANICAL CONTRACTORS, INC. | 3 | 70 | demolition, interior_remodel, mechanical | Jan 2026 |
| 21 | MAESTRO PLUMBING LLC | 3 | 54 | plumbing | May 2026 |
| 22 | QUALITY PLUMBING | 2 | 98 | electrical, fence, fire_alarm | Jun 2026 |
| 23 | REDLINE MECHANICAL INC | 2 | 93 | addition, interior_remodel, mechanical | May 2026 |
| 24 | Holaday Parks Inc | 2 | 91 | addition, electrical, ev_charger | May 2026 |
| 25 | PLUMBING WORKS | 2 | 91 | addition, demolition, fire_alarm | Apr 2026 |
"Score" is a 0–100 activity index from permit volume, recency, project value, and geographic reach. "Permits" counts building permits this contractor pulled in King County.
Query contractors, scores, and permits programmatically — GET /v1/contractors/search?state=WA&sort=score