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 |
|---|---|---|---|---|
| AT YOUR SERVICE REPAIR, INC. | Plumbing | Frederick County, Howard County | 116 | Jul 2026 |
| HEIL PLUMBING | Plumbing | Howard County | 77 | Jul 2026 |
| MEGA PLUMBING CORP | Plumbing | Frederick County, Howard County | 54 | Jul 2026 |
| EHRHARDT QUALITY PLUMBING | Plumbing | Howard County | 42 | Jul 2026 |
| LEN THE PLUMBER | Plumbing | Howard County | 27 | Jul 2026 |
| D. W. BAHR PLUMBING | Plumbing | Howard County | 22 | Jul 2026 |
| J. A. SMITH & CO. INC. | Plumbing | Frederick County, Howard County | 19 | Jul 2026 |
| CHASE PLUMBING & WELL SERVICES | Plumbing | Howard County | 16 | Jul 2026 |
| ROTO ROOTER SERVICES COMPANY | Plumbing | Howard County | 14 | Jul 2026 |
| TNT PLUMBING & DRAIN SERVICE, LLC | Plumbing | Frederick County, Howard County | 14 | Jul 2026 |
| CAPITAL CITY PLUMBING | Plumbing | Howard County | 11 | Jul 2026 |
| P J FITZPATRICK LLC | Plumbing | Howard County | 10 | Jul 2026 |
| BLACKSTONE PLUMBING AND ELECTRIC | Plumbing | Howard County | 9 | Jul 2026 |
| BUILD AND DESIGN CONTRUCTION INC. | Plumbing | Howard County | 8 | Jul 2026 |
| CASTAWAY PLUMBING | Plumbing | Frederick County, Howard County | 8 | Jun 2026 |
| CLARKSVILLE PLUMBING LLC | Plumbing | Howard County | 8 | Jul 2026 |
| PLUMB CHEAP INC | Plumbing | Howard County | 8 | Jul 2026 |
| PRIME PLUMBING | Plumbing | Howard County | 8 | Jul 2026 |
| GARTLAND PLUMBING INC | Plumbing | Howard County | 7 | Jun 2026 |
| KEYT DAVIS DBA FOCUSED PLUMBING & GAS, LLC | Plumbing | Howard County | 7 | Jun 2026 |
| LRT PLUMBING SERVICES LLC | Plumbing | Howard County | 7 | Jun 2026 |
| M & N PLUMBING LLC | Plumbing | Howard County | 7 | Jul 2026 |
| ROMAN MECHANICAL INC | Plumbing | Howard County | 7 | Jun 2026 |
| GARCIA'S MECHANICAL LLC | Plumbing | Howard County | 6 | Jul 2026 |
| JAOUAD ZOUINE | Plumbing | Howard County | 6 | Jul 2026 |
| A&A CONSTRUCTION AND UTILITIES, INC. | Plumbing | Howard County | 5 | Jul 2026 |
| AA ROOTER LLC DBA ROOTERMAN | Plumbing | Frederick County, Howard County | 5 | Jul 2026 |
| CARL STRINE PLUMBING & HEATING | Plumbing | Howard County | 5 | Jun 2026 |
| EVGENY CHERNOUSOV | Plumbing | Howard County | 5 | Jul 2026 |
| MID ATLANTIC COOPERATIVE SOLUTIONS DBA AERO ENERGY | Plumbing | Howard County | 5 | Jun 2026 |
| ONEIL PLUMBING | Plumbing | Howard County | 5 | Jun 2026 |
| AMERICAN MASTERS PLUMBING CO LLC | Plumbing | Howard County | 4 | Jun 2026 |
| CATONS PLUMBING, DRAINS AND HEATING | Plumbing | Howard County | 4 | Jun 2026 |
| CATONSVILLE PROFESSIONAL SERVICES | Plumbing | Howard County | 4 | Jul 2026 |
| CONFERS PLUMBING LLC | Plumbing | Howard County | 4 | Jun 2026 |
| C & S MECHANICAL, LLC | Plumbing | Howard County | 4 | Jul 2026 |
| ENDZEL PLUMBING LLC | Plumbing | Howard County | 4 | May 2026 |
| J & A CONSTRUCTION SERVICES, INC. | Plumbing | Howard County | 4 | Jun 2026 |
| KINSLEY CONSTRUCTION LLC | Plumbing | Frederick County, Howard County | 4 | Jun 2026 |
| Mallick Mechanical Contractors | Plumbing | Frederick County, Howard County | 4 | Jun 2026 |
| MCALLISTER PLUMBING INC | Plumbing | Howard County | 4 | Jul 2026 |
| MCGUIRE PLUMBING & HEATING, INC. | Plumbing | Howard County | 4 | Jul 2026 |
| OWINGS MECHANICAL | Plumbing | Howard County | 4 | Jul 2026 |
| PAUL VINCENT WOODS | Plumbing | Howard County | 4 | Jun 2026 |
| PLUMBING MASTERED, LLC | Plumbing | Howard County | 4 | Jul 2026 |
| PMC SERVICE LLC | Plumbing | Howard County | 4 | Jul 2026 |
| PUMPHREY PLUMBING LLC | Plumbing | Howard County | 4 | Jun 2026 |
| RAPID ROOTER PLUMBING COMPANY | Plumbing | Howard County | 4 | Jul 2026 |
| SUPERIOR MECHANICAL SERVICES | Plumbing | Frederick County, Howard County | 4 | Apr 2026 |
| THOMPSONGAS, LLC | Plumbing | Howard County | 4 | May 2026 |
Source: county permit records. Updated monthly.