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These guides explain what typical projects cost, how to compare providers and how to check licensing in Washington.
Who licenses contractors and lawyers in Washington
| Trade | Licensed by | Verify |
|---|---|---|
| HVAC | Washington State Department of Labor & Industries (L&I) | Check a license |
| Plumbing | Washington State Department of Labor & Industries (L&I) | Check a license |
| Electrical | Washington State Department of Labor & Industries (L&I) | Check a license |
| Roofing | Washington State Department of Labor & Industries (L&I) | Check a license |
| General / home-improvement contracting | Washington State Department of Labor & Industries (L&I) | Check a license |
| Attorneys | Washington State Bar Association (WSBA) | Check a license |
Compiled from each state agency's official site, checked November 15, 2026. Details and sources are on each trade page.
Building permits in Seattle
Residential building permits are issued by Seattle Department of Construction & Inspections (SDCI). Your contractor should normally pull the permit and schedule inspections.
Official permit office page, checked November 15, 2026.
Local businesses by trade in King County
How many employer businesses each trade has locally, from the Census Bureau's County Business Patterns.
| Service | Census industry | Locations | Employees |
|---|---|---|---|
| HVAC & plumbing | Plumbing, heating and air-conditioning contractors | 468 | 11,062 |
| Electrical | Electrical contractors and other wiring installation contractors | 477 | 9,306 |
| Roofing | Roofing contractors | 206 | 1,839 |
| General Contracting | Residential remodelers | 1,651 | 6,559 |
| Landscaping | Landscaping services | 843 | 5,653 |
| Painting | Painting and wall covering contractors | 531 | 3,367 |
| Flooring | Flooring contractors | 242 | 978 |
| Pest Control | Exterminating and pest control services | 44 | 531 |
| Residential Cleaning | Janitorial services | 649 | 7,129 |
| Moving | Used household and office goods moving | 106 | 1,048 |
| Home Security | Security systems services (except locksmiths) | 44 | 1,363 |
| Auto Repair | General automotive repair | 452 | 2,504 |
| Pet Services | Pet care (except veterinary) services | 217 | 1,688 |
| Tutoring | Exam preparation and tutoring | 137 | 1,582 |
| Accounting | Offices of certified public accountants | 507 | 7,297 |
| Legal | Offices of lawyers | 1,589 | 12,460 |
| Mortgage | Mortgage and nonmortgage loan brokers | 68 | 190 |
| Digital Marketing | Advertising agencies | 154 | 2,127 |
| IT Services | Computer systems design services | 936 | 12,904 |
Source: U.S. Census Bureau, County Business Patterns 2023. Employer establishments only. Checked November 15, 2026.
Seattle climate at a glance
Seattle averages 4,340 heating degree days and 282 cooling degree days a year, with 36.5 inches of precipitation. That shapes HVAC sizing and roofing choices; see the HVAC and roofing pages for what it means.
Source: NOAA NCEI U.S. Climate Normals 1991-2020, station USW00024234. Checked November 15, 2026.
Local notes for Seattle
Seattle pages for each service. HVAC, plumbing, electrical, roofing, contracting and lawyer pages include the licensing body, permit office, local firm counts and wages, with sources.
AllCityPros is an independent information resource and does not endorse or rate specific businesses. Sample directory entries from an earlier version of this site are kept for reference and are not verified.