The 25 contractors pulling the most building permits in King County, ranked by PermitStack's activity score — built from 116,548 permits on file. Updated from live public records.
| # | Contractor | Permits | Score | Top trades | Last permit |
|---|---|---|---|---|---|
| 1 | WASHINGTON GENERATORS LLC | 620 | 95 | electrical, ev_charger, hvac | Nov 2025 |
| 2 | BEST PLUMBING | 404 | 98 | addition, demolition, electrical | Apr 2026 |
| 3 | Tri State Plumbing Inc | 82 | 94 | hvac, interior_remodel, mechanical | Aug 2026 |
| 4 | EPIC PLUMBING LLC | 53 | 89 | electrical, fire_alarm, hvac | Jun 2026 |
| 5 | PIPEX INC | 43 | 82 | foundation, hvac, interior_remodel | Jun 2026 |
| 6 | Pye-Barker Fire & Safety, LLC | 40 | 99 | addition, demolition, electrical | Mar 2026 |
| 7 | JBAR PLUMBING LLC | 26 | 73 | hvac, interior_remodel, mechanical | Apr 2026 |
| 8 | WOLFE PLUMBING INC | 23 | 90 | electrical, fire_alarm, hvac | Jul 2026 |
| 9 | WALTS PLUMBING INC | 23 | 51 | plumbing | Jun 2026 |
| 10 | ACCO ENGINEERED SYSTEMS INC | 18 | 100 | addition, battery, demolition | Aug 2026 |
| 11 | McKinstry Co LLC | 18 | 100 | addition, battery, demolition | Jul 2026 |
| 12 | Hermanson Company LLP | 18 | 100 | addition, battery, demolition | Jul 2026 |
| 13 | FGMECHANICAL LLC | 17 | 60 | hvac, plumbing | Jan 2026 |
| 14 | GREENWOOD HEATING AND HOME SERVICES | 17 | 55 | hvac, plumbing | Jul 2026 |
| 15 | SEATTLE'S PLUMBING LLC | 17 | 54 | hvac, plumbing | Jun 2026 |
| 16 | MAESTRO PLUMBING LLC | 15 | 63 | plumbing, renovation | Jul 2026 |
| 17 | SJ TEDDY PLUMBING CNTRTRS LLC | 14 | 77 | electrical, hvac, interior_remodel | Jul 2026 |
| 18 | CAHILL'S PLUMBING & HEATING | 13 | 55 | plumbing | Jul 2026 |
| 19 | Northwest Plumbing Connection | 13 | 38 | plumbing | May 2026 |
| 20 | AUBURN MECHANICAL INC | 12 | 94 | addition, battery, demolition | Jun 2026 |
| 21 | JS PLUMBING INC | 12 | 87 | electrical, fire_alarm, hvac | Jun 2026 |
| 22 | OCEAN PARK MECHANICAL INC | 12 | 86 | addition, electrical, hvac | Jul 2026 |
| 23 | PROPLUMB LLC | 12 | 78 | hvac, plumbing, renovation | Jul 2026 |
| 24 | SMITH FIRE SYSTEMS INC | 11 | 100 | addition, demolition, electrical | May 2026 |
| 25 | AMERICAN MECHANICAL | 11 | 100 | demolition, electrical, hvac | Aug 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