Contractors active in Maryland county permit records, grouped from public filings. Counts reflect permits attributed to each firm. Not every filing names a contractor, so counts here are a floor. A firm's actual permit activity is usually higher.
| Contractor | Trade | Counties | Permits | Last active |
|---|---|---|---|---|
| CONSTELLATION HOME | HVAC | Frederick County, Howard County | 363 | Jul 2026 |
| SUNRUN INSTALLATION SERVICES INC | Solar | Frederick County, Howard County | 267 | Jul 2026 |
| AT YOUR SERVICE REPAIR, INC. | Plumbing | Frederick County, Howard County | 116 | Jul 2026 |
| SOLAR ENERGY WORLD | Solar | Frederick County, Howard County | 109 | Jul 2026 |
| FUSION SOLAR SERVICES LLC | Solar | Frederick County, Howard County | 106 | Jul 2026 |
| CECO, INC | Electrical | Frederick County, Howard County | 84 | Jul 2026 |
| BRYANT GROUP, INC. | Plumbing | Frederick County | 75 | Jul 2026 |
| JENSON FIRE PROTECTION INC | Fire Protection | Frederick County | 73 | Jul 2026 |
| ERIC SMOCK HEATING & A/C INC | HVAC | Frederick County | 56 | Jul 2026 |
| MEGA PLUMBING CORP | Plumbing | Frederick County, Howard County | 54 | Jul 2026 |
| KENNETH J LEMERE/SPARTAN ELEC | Electrical | Frederick County | 50 | Jul 2026 |
| Fence & Deck Connection | Deck & Patio | Baltimore County, Frederick County, Howard County | 47 | Jul 2026 |
| CELESTIAL SOLAR INNOVATIONS LLC | Solar | Frederick County, Howard County | 44 | Jul 2026 |
| ADT Security LLC | Electrical | Frederick County | 38 | Jul 2026 |
| ALBAUGH AND SONS FENCING | Deck & Patio | Frederick County | 34 | Jul 2026 |
| CULLIGAN WATER TREATMENT | Plumbing | Frederick County | 34 | Jul 2026 |
| D & L CLEAN POWER SOLUTIONS LLC | Solar | Frederick County, Howard County | 33 | Jun 2026 |
| BLAZEGUARD, INC. | Fire Protection | Frederick County | 32 | Jul 2026 |
| Ramiro A Fernandez | Electrical | Frederick County | 28 | Jul 2026 |
| ROBERT A TULL INC | Plumbing | Frederick County | 28 | Jul 2026 |
| CHEASAPEAKE PLUMBING & HEATING | Plumbing | Frederick County | 26 | Jun 2026 |
| PROVIDENT ELECTRIC | Electrical | Frederick County, Howard County | 26 | Jul 2026 |
| MICHAEL AND SON SERVICES, INC. | HVAC | Frederick County, Howard County | 23 | Jul 2026 |
| Tesla Energy Operations, Inc. Tesla Energy Operations, Inc. | Solar | Frederick County | 23 | Jul 2026 |
| TRINITY SOLAR LLC | Solar | Frederick County, Howard County | 23 | Jun 2026 |
| UNITED AIR TEMP | HVAC | Frederick County, Howard County | 23 | Jul 2026 |
| BEN LEWIS INC | Plumbing | Frederick County | 21 | Jul 2026 |
| TRI-STATE HOME SERVICES | HVAC | Frederick County | 21 | Jul 2026 |
| SILVER DOLLAR ELECTRIC INC. | Accessory Structure | Frederick County, Howard County | 20 | Jul 2026 |
| J. A. SMITH & CO. INC. | Plumbing | Frederick County, Howard County | 19 | Jul 2026 |
| PUTMAN PLUMBING INC | HVAC | Frederick County | 19 | Jul 2026 |
| ERCOLE ELECTRIC INC | Electrical | Frederick County | 18 | Jul 2026 |
| ROYAL ELECTRIC INC | Electrical | Frederick County, Howard County | 17 | Jul 2026 |
| ALL AROUND PLUMBING INC | Plumbing | Frederick County | 16 | Jul 2026 |
| JES CONSTRUCTION INC | Structural | Frederick County, Howard County | 16 | Jul 2026 |
| KCL ELECTRIC | Electrical | Frederick County, Howard County | 16 | Jul 2026 |
| BARRY DETWILER | Fire Protection | Frederick County | 15 | Jun 2026 |
| DAWN LAWSON | Accessory Structure | Frederick County | 15 | Jun 2026 |
| LARRY & SONS INC | HVAC | Frederick County | 15 | Jul 2026 |
| Tuckers Air Conditioning, Heating and Plumbing | HVAC | Frederick County | 15 | Jul 2026 |
| F.H. FURR PLMB, HTG, & A/C | HVAC | Frederick County | 14 | Jul 2026 |
| Nathan Burner | Plumbing | Frederick County | 14 | Jul 2026 |
| SCOTT MERCER LLC | Pool & Spa | Frederick County | 14 | Jul 2026 |
| TNT PLUMBING & DRAIN SERVICE, LLC | Plumbing | Frederick County, Howard County | 14 | Jul 2026 |
| WESLEY BARR | HVAC | Frederick County | 13 | Jul 2026 |
| BRICK STREET CONSTRUCTION, LLC | HVAC | Frederick County | 12 | Jun 2026 |
| J&R Plumbing & Heating | Pool & Spa | Frederick County, Howard County | 12 | Jul 2026 |
| LONG ELECTRIC LLC | Electrical | Frederick County, Howard County | 12 | Jun 2026 |
| PRECISION ELECTRICAL SOLUTIONS | Electrical | Frederick County | 12 | Jul 2026 |
| SPRINKLERS,LLC FIRE TECH RESID | Fire Protection | Frederick County | 12 | Jul 2026 |
Source: county permit records. Updated monthly.